build: disable -O3 for C++ coverage
The cflags
for --coverage
included -O0
so far, but that was
overridden by a later -O3
. Resolve that by adding
'cflags!': [ '-O3' ]
and increase coverage accuracy.
CI: https://ci.nodejs.org/job/node-test-commit/9087/
/cc @mhdawson @CurryKitten