* lib/tsan-dg.exp (tsan_init): Move check if tsan executable
	works from here ...
	(check_effective_target_fsanitize_thread): ... to here.  Do not
	specify additional compile flags for the test source.
	* lib/asan-dg.exp (check_effective_target_fsanitize_address): Do not
	specify additional compile flags for the test source.

From-SVN: r233106