libcore: Add a libcore-patch-style script

Checks style against recommendations in http://go/libcore-patch-style
and could be used a repohook.

Update sources based on issues found with script.

Bug: 111597837
Test: cd tools/patch-style/ && awk -f libcore-patch-style.awk test-input.txt
Test: find . -type f | xargs awk -f tools/patch-style/libcore-patch-style.awk
Change-Id: I641ed2951d00b848dec7a713e08b4b9fc076baea
39 files changed