[TrimmableTypeMap] Run full on-device test suite with trimmable type map

[simonrozsival]

Part of #10788
Related to #11017

Summary

The CI already runs the main on-device test suite (Mono.Android.NET-Tests.csproj + Java.Interop-Tests.NET.csproj) with multiple flavors: CoreCLR, NativeAOT, Interpreter, TrimModePartial, AotLlvm, etc. (see stage-package-tests.yaml). There is no flavor that sets _AndroidTypeMapImplementation=trimmable.

Before the trimmable type map can become the default, we need to run the full existing test suite with it and triage any failures.

What to do

1. Add a new CI test flavor

Add a new entry in build-tools/automation/yaml-templates/stage-package-tests.yaml:

- testName: TrimmableTypeMap
  extraBuildArgs: >-
    -p:TestsFlavor=TrimmableTypeMap
    -p:_AndroidTypeMapImplementation=trimmable
    -p:UseMonoRuntime=false

2. Handle expected exclusions

Some test categories will need to be excluded initially:

• NativeTypeMap — these tests call LLVM-specific APIs (TypeManager.GetJavaToManagedType, JNIEnv.TypemapManagedToJava). Tracked separately in [TrimmableTypeMap] Refactor NativeTypeMap tests to use runtime-agnostic type map API #11018 (refactor to runtime-agnostic API).
• Potentially Export — if [Export] methods don't work yet with the trimmable path ([TrimmableTypeMap] Fix [Export] JNI signature mapping for non-primitive parameter types #11047).

Add exclusion logic in Mono.Android.NET-Tests.csproj similar to the existing CoreCLR/NativeAOT exclusions:

<ExcludeCategories Condition=" '$(_AndroidTypeMapImplementation)' == 'trimmable' ">$(ExcludeCategories):NativeTypeMap</ExcludeCategories>

3. Triage and fix failures

Run the suite, categorize failures:

• Build failures — the trimmable build pipeline doesn't handle something the test project needs
• Runtime type resolution failures — types not found in the trimmable type map
• JCW/RegisterNatives failures — Java-to-managed callbacks broken
• Binding-specific failures — specific binding patterns the scanner doesn't handle

Each distinct failure class should get its own sub-issue if not already tracked.

Acceptance criteria

• A new TrimmableTypeMap test flavor exists in CI
• The full Mono.Android.NET-Tests suite builds and deploys with _AndroidTypeMapImplementation=trimmable
• Test results are triaged: passing tests pass, known gaps are excluded with tracking issues
• No unexpected regressions vs the CoreCLR flavor (same tests should pass minus known typemap gaps)

Dependencies

• The trimmable build pipeline must be functional end-to-end ([TrimmableTypeMap] Implement pre-trimming build task #10789, [TrimmableTypeMap] MSBuild task + targets wiring + incremental builds #10800, [TrimmableTypeMap] Build pipeline: targets, stubs, manifest integration, feature switches #11036)
• [TrimmableTypeMap] Refactor NativeTypeMap tests to use runtime-agnostic type map API #11018 should ideally land first so NativeTypeMap tests work with both paths

Notes

This is the broadest validation of the trimmable type map. The existing test sub-issues in #11017 target specific test files; this issue is about running everything and seeing what breaks.