Add a testcase for PR ld/22751

Add a testcase for PR ld/22751

Since dummy.o must be placed before

-Wl,--whole-archive tmpdir/pr22751.a -Wl,--no-whole-archive

to trigger the bug, this patch adds an optional trailing ld options to
run_ld_link_exec_tests.

	PR ld/22751
	* testsuite/config/default.exp (INT128_CFLAGS): New.
	* testsuite/ld-plugin/lto.exp (INT128_CFLAGS): New.
	Run ld/22751 tests.
	* testsuite/ld-plugin/pr22751.c: New file.
	* testsuite/lib/ld-lib.exp (run_ld_link_exec_tests): Add
	ld trailing options.