JnienvArrayMarshaling.GetObjectArray fails on CoreCLR with emulator 36.4.10

## Description

`Android.RuntimeTests.JnienvArrayMarshaling.GetObjectArray` consistently fails on CoreCLR (Release) when running on Android emulator 36.4.10 (previously passing on emulator 32.1.9).

The test passes on MonoVM and NativeAOT — only CoreCLR is affected.

## Error
```
Expected: True
But was: False
```

The assertion comes from `AssertArrays` which lacks diagnostic output, so we don't know what values CoreCLR returns.

## Repro
- Emulator: 36.4.10 (package 15004761)
- Runtime: CoreCLR
- Test: `tests/Mono.Android-Tests/Mono.Android-Tests/Android.Runtime/JnienvArrayMarshaling.cs` line 267

## Context
Discovered in #10971 (emulator bump PR). The test was ignored on CoreCLR to unblock the emulator update.

## Next Steps
1. Add diagnostic output to `GetObjectArray` / `AssertArrays` to understand what values come back
2. Investigate CoreCLR-specific JNI array marshaling difference with newer ART runtime