Revert MonoAndroidExportTest changes that force trimmable typemap

The _AndroidTypeMapImplementation=trimmable forcing and Assert.Ignore
removal for NativeAOT belong in the separate CI setup PR, not here.
This PR should only add the Export code generation support without
modifying CI configuration or device test behavior.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: simonrozsival

tests/MSBuildDeviceIntegration/Tests/MonoAndroidExportTest.cs

@@ -22,6 +22,9 @@ public void MonoAndroidExportReferencedAppStarts (
 			[Values] bool isRelease,
 			[Values] AndroidRuntime runtime)
 		{
+			if (runtime == AndroidRuntime.NativeAOT) {
+				Assert.Ignore ("NativeAOT does not support Mono.Android.Export");
+			}
 			if (IgnoreUnsupportedConfiguration (runtime, release: isRelease)) {
 				return;
 			}
@@ -34,9 +37,6 @@ public void MonoAndroidExportReferencedAppStarts (
 				},
 			};
 			proj.SetRuntime (runtime);
-			if (runtime == AndroidRuntime.CoreCLR || runtime == AndroidRuntime.NativeAOT) {
-				proj.SetProperty ("_AndroidTypeMapImplementation", "trimmable");
-			}
 			proj.Sources.Add (new BuildItem.Source ("ContainsExportedMethods.cs") {
 				TextContent = () => @"using System;
 using Java.Interop;
@@ -112,6 +112,9 @@ public void ExportedMembersSurviveGarbageCollection (
 			[Values] bool isRelease,
 			[Values] AndroidRuntime runtime)
 		{
+			if (runtime == AndroidRuntime.NativeAOT) {
+				Assert.Ignore ("NativeAOT does not support Mono.Android.Export");
+			}
 			if (IgnoreUnsupportedConfiguration (runtime, release: isRelease)) {
 				return;
 			}
@@ -124,9 +127,6 @@ public void ExportedMembersSurviveGarbageCollection (
 				},
 			};
 			proj.SetRuntime (runtime);
-			if (runtime == AndroidRuntime.CoreCLR || runtime == AndroidRuntime.NativeAOT) {
-				proj.SetProperty ("_AndroidTypeMapImplementation", "trimmable");
-			}
 			proj.Sources.Add (new BuildItem.Source ("ContainsExportedMethods.cs") {
 				TextContent = () => @"using System;
 using Java.Interop;
@@ -157,13 +157,14 @@ protected override void OnCreate (Bundle bundle)
 
 			var foo = new ContainsExportedMethods ();
 
-			// Force GC to verify the registered callback does not rely on transient state.
+			// Force GC to collect any unrooted delegates
 			for (int i = 0; i < 10; i++) {
 				GC.Collect ();
 				GC.WaitForPendingFinalizers ();
 			}
 
-			// Invoke the [Export] method through JNI to validate the generated callback path.
+			// Invoke the [Export] method through JNI (Java -> native delegate -> C#)
+			// This path crashes with SIGABRT if the delegate was garbage collected
 			IntPtr klass = JNIEnv.GetObjectClass (foo.Handle);
 			IntPtr methodId = JNIEnv.GetMethodID (klass, ""Exported"", ""()V"");
 			JNIEnv.CallVoidMethod (foo.Handle, methodId);