Call clang-tidy with -quiet unless WITH_TIDY is set.

* Default builds calls clang-tidy only if enabled locally.
  In this case, clang-tidy should be quiet.
* If WITH_TIDY is 1 or true, let clang-tidy emit default messages.
* Even with -quiet and all warnings are suppressed,
  clang-tidy emits one line message of the number of suppressed messages.
  This one-liner could be suppressed in future changes.

Bug: 69051430
Test: default build and build with WITH_TIDY=1
Change-Id: I45303149930b33544e271e6d5eeddf18c9e48d7a