Run a few more binutils tests non-native

Setting CC_FOR_TARGET from the environment CC was just plain wrong,
and no doubt the reason these tests were only run natively.

	* testsuite/binutils-all/compress.exp (test_gnu_debuglink): Don't
	set CC_FOR_TARGET.  Run test non-native.
	* testsuite/binutils-all/objdump.exp (test_build_id_debuglink):
	Likewise.
	(test_follow_debuglink): Run test non-native.