am 36629d29: Merge remote-tracking branch \'aosp/upstream-dev\' into merge

* commit '36629d29adb4c02683a890d7590ac38ce5c29d92': (93 commits)
  Reduce variables scope
  Force initialization of the init_lock in malloc_init_hard on Windows XP
  Fix pointer comparision with undefined behavior.
  Optimize arena_prof_tctx_set().
  Fix TLS configuration.
  Don't purge junk filled chunks when shrinking huge allocations
  Fix chunk purge hook calls for in-place huge shrinking reallocation.
  Fix arenas_cache_cleanup() and arena_get_hard().
  Add JEMALLOC_CXX_THROW to the memalign() function prototype.
  Fix arenas_cache_cleanup().
  Silence compiler warnings for unreachable code.
  Rename index_t to szind_t to avoid an existing type on Solaris.
  Don't bitshift by negative amounts.
  Update ChangeLog for 4.0.0.
  Improve arena.<i>.chunk_hooks documentation formatting.
  Update in-place reallocation documentation.
  Update large/huge size class cutoff documentation.
  Fix a comment.
  Fix gcc build failure (define __has_builtin).
  Check whether gcc version supports __builtin_unreachable().
  ...