Regressions on master at commit r16-5353 vs commit r16-5336 on Linux/x86_64

[Haochen Jiang via Gcc-regression]

Regressions on master at commit r16-5353 vs commit r16-5336 on Linux/x86_64
New failures:
FAIL: objc/execute/IMP.m compilation,  -O0 -fgnu-runtime

New passes:
FAIL: 30_threads/async/async.cc  -std=gnu++17 execution test