Hi

There are a few instruction in AArch64 that are in the HINT space. Any of these instructions should
be accepted by the assembler/disassembler at any architecture version. This patch fixes the existing
instructions that are not behaving accordingly.
I have used all of the instructions mentioned in the following to make the changes:
https://developer.arm.com/docs/ddi0596/f/base-instructions-alphabetic-order/hint-hint-instruction

Build and regression tested on aarch64-none-linux-gnu.
Is this okay for trunk and a backport for 2.34?

Thanks
Sudi
PS: I have not added the regenerated files to the patch to make it easier for review. I will add them
to the final commit. 

gas/ChangeLog:

2020-xx-xx  Sudakshina Das  <sudi.das@arm.com>

	* testsuite/gas/aarch64/bti.d: Update -march option.
	* testsuite/gas/aarch64/illegal-bti.d: Remove.
	* testsuite/gas/aarch64/illegal-bti.l: Remove.
	* testsuite/gas/aarch64/illegal-ras-1.l: Remove esb.
	* testsuite/gas/aarch64/illegal-ras-1.s: Remove esb.

opcodes/ChangeLog:

2020-xx-xx  Sudakshina Das  <sudi.das@arm.com>

	* aarch64-tbl.h (aarch64_feature_bti, BTI, BTI_INSN): Remove.
	(aarch64_feature_ras, RAS): Likewise.
	(aarch64_feature_stat_profile, STAT_PROFILE): Likewise.
	(aarch64_opcode_table): Update bti, xpaclri, pacia1716, pacib1716,
	autia1716, autib1716, esb, psb, dgh, paciaz, paciasp, pacibz, pacibsp,
	autiaz, autiasp, autibz, autibsp to be CORE_INSN.
	* aarch64-asm-2.c: Regenerated.
	* aarch64-dis-2.c: Regenerated.
	* aarch64-opc-2.c: Regenerated.