x86_64 k1om tests

On x86_64-nacl we currently see
FAIL: Absolute non-overflowing relocs
FAIL: ld-x86-64/protected2-k1om
FAIL: ld-x86-64/protected3-k1om

This limits the tests as per the l1om variants.

	* testsuite/ld-x86-64/abs-k1om.d: Run only on x86_64-*-linux*.
	* testsuite/ld-x86-64/protected2-k1om.d: Likewise.
	* testsuite/ld-x86-64/protected3-k1om.d: Likewise.