testsuite, rs6000: Make powerpc_vsx consider current_compiler_flags [PR114842]

testsuite, rs6000: Make powerpc_vsx consider current_compiler_flags [PR114842]

As noted in PR114842, most of the test cases which require
effective target check powerpc_vsx_ok actually care about
if VSX feature is enabled, and they should adopt effective
target powerpc_vsx instead.  By considering we already have
a number of test cases having explicit -mvsx in dg-options
etc., to keep them still be tested as before even without
vsx enabled by default, this patch is to make powerpc_vsx
consider current_compiler_flags.

	PR testsuite/114842

gcc/testsuite/ChangeLog:

	* lib/target-supports.exp (check_effective_target_powerpc_vsx): Take
	current_compiler_flags into account.