Merge the android-9.0.0_r55 release tag
Android 9.0.0 Release 55 (6197209)

* tag 'android-9.0.0_r55':
  DO NOT MERGE: Fix bug in random.
  DO NOT MERGE: [libc++] Move __clamp_to_integral to <cmath>, and harden against min()/max() macros
  DO NOT MERGE: [libc++] Add `__truncating_cast` for safely casting float types to integers
  DO NOT MERGE: Suppress warnings in tests.

Change-Id: Ib4252c4e85eb89b2561cdc86fee0bcf746b5f0b1