Add regression tests for #904.

The goal is to ensure that ill-formed JVMSetup blocks are caught
at an early stage by `crucible_jvm_unsafe_assume_spec`.

The tests also include a bunch of known false positives for other
well-formedness checks on JVMSetup blocks that we do not perform
yet.

intTests/test_jvm_setup_errors/Makefile

@@ -0,0 +1,2 @@
+%.class: %.java
+	javac -g $<

intTests/test_jvm_setup_errors/Test.java

@@ -0,0 +1,17 @@
+class Test
+{
+    long val;
+
+    long get () {
+        return val;
+    }
+    void set (long x) {
+        val = x;
+    }
+    boolean lessThan (Test t) {
+        return val < t.val;
+    }
+    static long lookup (long arr[], int idx) {
+        return arr[idx];
+    }
+}