Fix nondeterminism in WriteOptionsTest

[Shiyang-Zhao]

This PR fixes nondeterministic behavior in the following flaky tests:

• com.cedarsoftware.io.WriteOptionsTest.getAccessorsForClass_bindsBooleanNonStaticFieldAccessors
• com.cedarsoftware.io.WriteOptionsTest.getAccessorsForClass_findEnumWithCustomFields_whenNotPublicFieldsOnly
• com.cedarsoftware.io.WriteOptionsTest.getAccessorsForClass_findsAllNonStaticFieldAccessors
• com.cedarsoftware.io.WriteOptionsTest.getAccessorsForClass_whenMethodDoesNotExists_doesNotThrowException
• com.cedarsoftware.io.WriteOptionsTest.getAccessorsForClass_withMixedAccessors

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Description

All five tests flaked due to the nondeterministic ordering of fields and methods returned by Java reflection.
WriteOptions.getAccessorsForClass() constructs its accessor list using reflection, which does not guarantee deterministic ordering, yet the original tests assumed fixed positional order (e.g., index 0 must be "x").

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Failure messages:

1. getAccessorsForClass_bindsBooleanNonStaticFieldAccessors

[ERROR] com.cedarsoftware.io.WriteOptionsTest.getAccessorsForClass_bindsBooleanNonStaticFieldAccessors -- Time elapsed: 0.223 s <<< FAILURE!
org.opentest4j.AssertionFailedError: expected: <test3> but was: <test1>
    at org.junit.jupiter.api.AssertionFailureBuilder.build(AssertionFailureBuilder.java:151)
    at org.junit.jupiter.api.AssertionFailureBuilder.buildAndThrow(AssertionFailureBuilder.java:132)
    at org.junit.jupiter.api.AssertEquals.failNotEqual(AssertEquals.java:197)
    at org.junit.jupiter.api.AssertEquals.assertEquals(AssertEquals.java:182)
    at org.junit.jupiter.api.AssertEquals.assertEquals(AssertEquals.java:177)
    at org.junit.jupiter.api.Assertions.assertEquals(Assertions.java:1145)
    at com.cedarsoftware.io.WriteOptionsTest.getAccessorsForClass_bindsBooleanNonStaticFieldAccessors(WriteOptionsTest.java:571)
    at java.base/java.lang.reflect.Method.invoke(Method.java:569)
    at java.base/java.util.ArrayList.forEach(ArrayList.java:1511)
    at java.base/java.util.ArrayList.forEach(ArrayList.java:1511)

2. getAccessorsForClass_findEnumWithCustomFields_whenNotPublicFieldsOnly

[ERROR] com.cedarsoftware.io.WriteOptionsTest.getAccessorsForClass_findEnumWithCustomFields_whenNotPublicFieldsOnly -- Time elapsed: 0.240 s <<< FAILURE!
org.opentest4j.AssertionFailedError: expected: <isStick> but was: <tire>
    at org.junit.jupiter.api.AssertionFailureBuilder.build(AssertionFailureBuilder.java:151)
    at org.junit.jupiter.api.AssertionFailureBuilder.buildAndThrow(AssertionFailureBuilder.java:132)
    at org.junit.jupiter.api.AssertEquals.failNotEqual(AssertEquals.java:197)
    at org.junit.jupiter.api.AssertEquals.assertEquals(AssertEquals.java:182)
    at org.junit.jupiter.api.AssertEquals.assertEquals(AssertEquals.java:177)
    at org.junit.jupiter.api.Assertions.assertEquals(Assertions.java:1145)
    at com.cedarsoftware.io.WriteOptionsTest.getAccessorsForClass_findEnumWithCustomFields_whenNotPublicFieldsOnly(WriteOptionsTest.java:588)
    at java.base/java.lang.reflect.Method.invoke(Method.java:569)
    at java.base/java.util.ArrayList.forEach(ArrayList.java:1511)

3. getAccessorsForClass_findsAllNonStaticFieldAccessors

[ERROR] com.cedarsoftware.io.WriteOptionsTest.getAccessorsForClass_findsAllNonStaticFieldAccessors -- Time elapsed: 0.237 s <<< FAILURE!
org.opentest4j.AssertionFailedError: expected: <test3> but was: <test1>
    at org.junit.jupiter.api.AssertionFailureBuilder.build(AssertionFailureBuilder.java:151)
    at org.junit.jupiter.api.AssertionFailureBuilder.buildAndThrow(AssertionFailureBuilder.java:132)
    at org.junit.jupiter.api.AssertEquals.failNotEqual(AssertEquals.java:197)
    at org.junit.jupiter.api.AssertEquals.assertEquals(AssertEquals.java:182)
    at org.junit.jupiter.api.AssertEquals.assertEquals(AssertEquals.java:177)
    at org.junit.jupiter.api.Assertions.assertEquals(Assertions.java:1145)
    at com.cedarsoftware.io.WriteOptionsTest.getAccessorsForClass_findsAllNonStaticFieldAccessors(WriteOptionsTest.java:556)
    at java.base/java.lang.reflect.Method.invoke(Method.java:569)
    at java.base/java.util.ArrayList.forEach(ArrayList.java:1511)

4. getAccessorsForClass_whenMethodDoesNotExists_doesNotThrowException

[ERROR] com.cedarsoftware.io.WriteOptionsTest.getAccessorsForClass_whenMethodDoesNotExists_doesNotThrowException -- Time elapsed: 0.274 s <<< FAILURE!
org.opentest4j.AssertionFailedError: 
expected: "getTotal"
 but was: "y"
    at com.cedarsoftware.io.WriteOptionsTest.getAccessorsForClass_whenMethodDoesNotExists_doesNotThrowException(WriteOptionsTest.java:533)
    at java.base/java.lang.reflect.Method.invoke(Method.java:569)
    at java.base/java.util.ArrayList.forEach(ArrayList.java:1511)

5. getAccessorsForClass_withMixedAccessors

[ERROR] com.cedarsoftware.io.WriteOptionsTest.getAccessorsForClass_withMixedAccessors -- Time elapsed: 0.271 s <<< FAILURE!
org.opentest4j.AssertionFailedError: 
expected: "x"
 but was: "y"
    at com.cedarsoftware.io.WriteOptionsTest.getAccessorsForClass_withMixedAccessors(WriteOptionsTest.java:460)
    at java.base/java.lang.reflect.Method.invoke(Method.java:569)
    at java.base/java.util.ArrayList.forEach(ArrayList.java:1511)

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Proposed Changes

• Removed index-based assumptions in tests (list.get(0), list.get(1), etc.).
• Rewrote tests to use deterministic map lookups: Map<String, Accessor> map = accessors.stream().collect(...)
• Validated accessor properties (name, type, declaring class, visibility) rather than relying on list positions.
• No production code was changed — test-only modification.