[binutils][aarch64] Add SVE2 tests

[binutils][aarch64] Add SVE2 tests

Add tests that SVE2 instructions are encoded as they should be, and
tests that invalid instructions have their problems reported.

Also check that each sve2 cryptographic extension is required to use the
corresponding cryptographic instructions.

Finally, test to ensure that sve2 instructions using mnemonics that
exist in sve1 still need the sve2 feature to be used.

gas/ChangeLog:

2019-05-09  Matthew Malcomson  <matthew.malcomson@arm.com>

	* testsuite/gas/aarch64/illegal-sve2-aes.d: New test.
	* testsuite/gas/aarch64/illegal-sve2-bitperm.d: New test.
	* testsuite/gas/aarch64/illegal-sve2-sha3.d: Test new instructions.
	* testsuite/gas/aarch64/illegal-sve2-sm4.d: Test new instructions.
	* testsuite/gas/aarch64/illegal-sve2-sve1ext.d: Test new instructions.
	* testsuite/gas/aarch64/illegal-sve2-sve1ext.l: Test new instructions.
	* testsuite/gas/aarch64/illegal-sve2.d: Test new instructions.
	* testsuite/gas/aarch64/illegal-sve2.l: Test new instructions.
	* testsuite/gas/aarch64/illegal-sve2.s: Test new instructions.
	* testsuite/gas/aarch64/sve1-extended-sve2.s: New test.
	* testsuite/gas/aarch64/sve2.d: Test new instructions.
	* testsuite/gas/aarch64/sve2.s: Test new instructions.