ld: Pass -fno-lto to non LTO tests

ld: Pass -fno-lto to non LTO tests

	* testsuite/config/default.exp (NOLTO_CFLAGS): New.
	* ld/testsuite/ld-elfcomm/elfcomm.exp: Add $NOLTO_CFLAGS to CC.
	* testsuite/ld-elfvers/vers.exp: Likewise.
	* testsuite/ld-elfvsb/elfvsb.exp: Likewise.
	* testsuite/ld-gc/gc.exp: Likewise.
	* testsuite/ld-plugin/plugin.exp: Likewise.
	* testsuite/ld-scripts/crossref.exp: Likewise.
	* testsuite/ld-selective/selective.exp: Likewise.
	* testsuite/ld-undefined/undefined.exp: Likewise.
	* testsuite/ld-srec/srec.exp: Add $NOLTO_CFLAGS to CC.  Override
	CXXFLAGS.
	* testsuite/lib/ld-lib.exp (run_ld_link_tests): Prepend -fno-lto
	to cflags.