Re: Add support for a .base64 pseudo-op to gas

Fixes a failure on rx-elf where the standard data section isn't .data.
run_dump_test has machinery to translate .data in both options and
expected results for objdump, but not for readelf -x.

	PR 31964
	* testsuite/gas/all/base64.d: Dump .data with objdump.  Run on
	all targets.