Revert "Revert "Build System: Validate AndroidTest.xml Configs""

This reverts commit 054f210f.

Reason for revert: Revert it again since BUG of 109736180 already be fixed.
                   Local verified for different build targets of
                   walleye_coverage-userdebug, marlin_coverage-userdebug
                   and make sure they can build pass.
BUG: 109736180
Test: lunch walleye_coverage-userdebug; make adbd_test

BUG: 73082610
Test: cd packages/apps/DocumentsUI/tests/; mma
      Modify AndroidTest.xml to a not well-formed xml; mma
      Then, it should build fail.
      atest -v DocumentsUITests

Change-Id: Iadfcb28a4e3f685a66697de21f57ca5bdb8b7c9e