Add intra-core API required by conscrypt

An initial set of methods that need to be visible in
the intra-core API surface for conscrypt to compile.

There's a fix in JavaLibrary.bp to the core-current-stubs-gen
target to stop files in openjdk_mmodule_extra_files showing
up in the core.current.stubs.

Bug: 110404540
Bug: 113148576
Test: build
Change-Id: I4bade4dac925cfcb14df9335918319be897ac50d
diff --git a/JavaLibrary.bp b/JavaLibrary.bp
index ae84030..c8044fc 100644
--- a/JavaLibrary.bp
+++ b/JavaLibrary.bp
@@ -525,7 +525,9 @@
     srcs: [":core_api_files"],
     installable: false,
     no_framework_libs: true,
-    args: " --exclude-annotations",
+    args: " --exclude-annotations "
+        + "--hide-annotation libcore.api.Hide",
+    merge_inclusion_annotations_dirs: ["ojluni-annotated-mmodule-stubs"],
 }
 
 // A library containing the parts of the public SDK API provided by the core libraries.