Make ARMv8-M GAS tests pass on non ELF targets

Make ARMv8-M GAS tests pass on non ELF targets

2016-05-17  Thomas Preud'homme  <thomas.preudhomme@arm.com>

gas/
	* testsuite/gas/arm/archv8m-cmse-msr-base.d: Force Thumb when
	disassembling and stop skipping targets.
	* testsuite/gas/arm/archv8m-cmse-msr-main.d: Likewise.
	* testsuite/gas/arm/archv8m-main-dsp-4.d: Likewise.
	* testsuite/gas/arm/archv8m-base.d: Also allow nops after the last
	instruction for targets that have stronger alignment requirement.
	* testsuite/gas/arm/archv8m-cmse-base.d: Likewise.
	* testsuite/gas/arm/archv8m-cmse-main-1.d: Likewise.
	* testsuite/gas/arm/archv8m-cmse-main-2.d: Likewise.
	* testsuite/gas/arm/archv8m-main-dsp-1.d: Likewise.
	* testsuite/gas/arm/archv8m-main-dsp-2.d: Likewise.
	* testsuite/gas/arm/archv8m-main-dsp-3.d: Likewise.
	* testsuite/gas/arm/archv8m-main.d: Likewise.
	* testsuite/gas/arm/archv8m.s: Add label.
	* testsuite/gas/arm/archv8m-cmse.s: Likewise.
	* testsuite/gas/arm/archv8m-cmse-msr.s: Likewise.
	* testsuite/gas/arm/archv8m-cmse-main.s: Likewise.