Add core-lambda-stubs to classpath

Add core-lambda-stubs to the bootclasspath for modules with no
sdk_version or with sdk_version: "current", and to the classpath
for modules that specify a specific sdk_version number.  Use the
prebuilt sdk-core-lambda-stubs when using a prebuilt SDK.

Fixes compiling modules with lambdas against the SDK.

This reapplies I5e700f2dd86f1a6b84b7a55dd9bfe21a448d3fb6 with fixes
and tests for unbundled builds.

Bug: 80428539
Test: java_test.go
Change-Id: Ib7aaeebb93137270d7336a7293a08ed7064a3184
diff --git a/java/aar.go b/java/aar.go
index 21e38a4..415170e 100644
--- a/java/aar.go
+++ b/java/aar.go
@@ -213,7 +213,7 @@
 
 	sdkDep := decodeSdkDep(ctx, sdkVersion)
 	if sdkDep.useFiles {
-		sharedLibs = append(sharedLibs, sdkDep.jar)
+		sharedLibs = append(sharedLibs, sdkDep.jars...)
 	}
 
 	ctx.VisitDirectDeps(func(module android.Module) {