Report DiffStatus for access specifiers

If a class member's access specifier is less restricted than the old
declaration, header-abi-diff reports it as an extension rather than
no difference.

Bug: 323447559
Test: ANDROID_BUILD_TOP=`realpath .` \
      PATH=$PATH:`realpath out/soong/dist/bin` \
      development/vndk/tools/header-checker/tests/test.py
Change-Id: I91b5e47d3d118db2c7bf07579cc60189f4e6c139
4 files changed