* Initial implementation for contract customization

fix build errors

Move converter rooting to DefaultJsonTypeInfoResolver so that it can be used standalone

Fix ConfigurationList.IsReadOnly

Minor refactorings (#1)

* Makes the following changes:

* Move singleton initialization for DefaultTypeInfoResolver behind a static property.
* Consolidate JsonSerializerContext & IJsonTypeInfoResolver values to a single field.
* Move reflection fallback logic away from JsonSerializerContext and into JsonSerializerOptions

* Update src/libraries/System.Text.Json/src/System/Text/Json/Serialization/JsonSerializerOptions.cs

* remove testing of removed field

Simplify the JsonTypeInfo.CreateObject implemenetation (#2)

* Simplify the JsonTypeInfo.CreateObject implemenetation

* Update src/libraries/System.Text.Json/src/System/Text/Json/Serialization/Metadata/JsonTypeInfoOfT.cs

* Update src/libraries/System.Text.Json/src/System/Text/Json/Serialization/Metadata/JsonTypeInfoOfT.cs

Co-authored-by: Krzysztof Wicher <[email protected]>

Co-authored-by: Krzysztof Wicher <[email protected]>

Tests and fixes for JsonTypeInfoKind.None

TypeInfo type mismatch tests

Allow setting NumberHandling on JsonTypeInfoKind.None

test resolver returning wrong type of options

JsonTypeInfo/JsonPropertyInfo mutability tests

rename test file

Move default converter rooting responsibility behind DefaultJsonTypeInfoResolver (#3)

* Move default converter rooting responsibility behind DefaultJsonTypeInfoResolver

* address feedback

Add simple test for using JsonTypeInfo<T> with APIs directly taking it

fix and tests for untyped/typed CreateObject

uncomment test cases, remove todo

More tests and tiny fixes

Add a JsonTypeInfoResolver.Combine test for JsonSerializerContext (#4)

* Fix JsonTypeInfoResolver.Combine for JsonSerializerContext

* Break up failing test

Fix simple scenarios for combining contexts (#6)

* Fix simple scenarios for combining contexts

* feedback

JsonSerializerContext combine test with different camel casing

Remove unneeded virtual calls & branching when accessing Get & Set delegates (#7)

JsonPropertyInfo tests everything minus ShouldSerialize & NumberHandling

Update src/libraries/System.Text.Json/src/System/Text/Json/Serialization/JsonConverterOfT.cs

Update src/libraries/System.Text.Json/src/System/Text/Json/Serialization/JsonConverterOfT.cs

throw InvalidOperationException rather than ArgumentNullException for source gen when PropertyInfo.Name is assigned through JsonPropertyInfoValues

tests for duplicated property names and JsonPropertyInfo.NumberHandling

Add tests for NumberHandling and failing tests for ShouldSerialize

disable the failing test and add extra checks

disable remainder of the failing ShouldSerialize tests, fix working one

Fix ShouldSerialize and IgnoreCondition interop

Add failing tests for CreateObject + parametrized constructors

Fix CreateObject support for JsonConstructor types (dotnet#10)

* Fix CreateObject support for JsonConstructor types

* address feedback

Make contexts more combinator friendly (#9)

* Make contexts more combinator friendly

* remove converter cache

* redesign test to account for JsonConstructorAttribute

* Combine unit tests

* address feedback

* Add acceptance tests for DataContract attributes & Specified pattern (dotnet#11)

* Add private field serialization acceptance test (dotnet#13)

* tests, PR feedback (dotnet#14)

* PR feedback and extra tests

* Shorten class name, remove incorrect check (not true for polimorphic cases)

* Make parameter matching for custom properties map property Name with parameter (dotnet#16)

* Test static initialization with JsonTypeInfo (dotnet#17)

* Fix test failures and proper fix this time (dotnet#18)

* Fix test failures and proper fix this time

* reinstate ActiveIssueAttribute

* PR feedback and adjust couple of tests which don't set TypeInfoResolver

* fix IAsyncEnumerable tests

* Lock JsonSerializerOptions in JsonTypeInfo.EnsureConfigured()

Co-authored-by: Eirik Tsarpalis <[email protected]>

Co-authored-by: Eirik Tsarpalis <[email protected]>

Fixes dotnet#95367.

Relevant part of the JitDump:

```
Using `if true` assertions from pred BB02
Assertions in: #1
fgMorphTree BB04, STMT00021 (before)
               [000070] DA---------                         *  STORE_LCL_VAR ubyte  V10 tmp9
               [000057] -----------                         \--*  CAST      int <- ubyte <- int
               [000006] -----------                            \--*  EQ        int
               [000004] -----------                               +--*  LCL_VAR   ref    V02 tmp1          (last use)
               [000055] H----------                               \--*  CNS_INT(h) ref     'Frozen EmptyPartition`1<Int32> object'

Assertion prop for index #1 in BB04:
               [000006] -----------                         *  EQ        int
GenTreeNode creates assertion:
               [000070] DA---+-----                         *  STORE_LCL_VAR ubyte  V10 tmp9
In BB04 New Local Constant Assertion: V10 == [0000000000000001], index = #2

fgMorphTree BB04, STMT00021 (after)
               [000070] DA---+-----                         *  STORE_LCL_VAR ubyte  V10 tmp9
               [000055] H----+-----                         \--*  CNS_INT(h) int
```

The JitDump is unfinished because the compiler crashes when trying to dump the last line. Clearly, the `CNS_INT` is no longer a handle at that point because we just bashed it to a constant 1.