Simplify DEFAULT_LOCAL_TIDY_CHECKS.

* Now each local directory path is matched against multiple
  patterns and only the last matched one will be used,
  or the DEFAULT_GLOBAL_TIDY_CHECKS is used.

Bug: http://b/27779618
Change-Id: I786e6cacd8a680a034b4bc09f561f658177d9b17
Test: build with WITH_TIDY=1.