Run test build: Refactor javac_wrapper.sh usage.

It turns out the tests don't need to replace javac behaviour,
they just want to perform custom action after the compilation.

Let the python script do the javac compilation as usual
(which automatically adds RBE support for those tests),
add call javac_post.sh after the compilation instead.

Test: Build artifacts are identical as before.
Change-Id: I9093968ba678706815bc7c2eef6380d454975f9b
diff --git a/test/091-override-package-private-method/javac_post.sh b/test/091-override-package-private-method/javac_post.sh
new file mode 100755
index 0000000..d2dd7e6
--- /dev/null
+++ b/test/091-override-package-private-method/javac_post.sh
@@ -0,0 +1,20 @@
+#!/bin/bash
+#
+# Copyright (C) 2022 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+set -e # Stop on error - the caller script may not have this set.
+
+mkdir -p classes-ex
+mv classes/OverridePackagePrivateMethodSuper.class classes-ex