When 'no_default_flags' is true only flags passed using '--param=compile_flags'
and '--param=link_flags' will be used when compiling the tests. This option
can be used to run the test suite against libstdc++ and helps with all
unusual test suite configurations.
NOTE: sanitizer flags are still added when '--param=use_sanitizer' is used even
if '--param=no_default_flags' is given.
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@226322 91177308-0d34-0410-b5e6-96231b3b80d8
ae8bc6b3ef