Android patch: Fix message2 test setup issue on Android

1. "}" is a special character in regex, and needs to be escaped
  on Android.
2. cls.getClassLoader().getResource(packageName) returns null on
   Android.

This patch can be upstreamed.

Test: atest CtsIcuTestCases:android.icu.dev.test.message2
Change-Id: I0c3b33bfc9d8dfa192a73a268ca068e1c3a3cf1e
4 files changed