AArch64: Add more accurate constraint [PR117292]

AArch64: Add more accurate constraint [PR117292]

As shown in the PR, reload may only check the constraint in some cases and
and not check the predicate is still valid for the resulting instruction.
To fix the issue, add a new constraint which matches the predicate exactly.

gcc/ChangeLog:
	PR target/117292
	* config/aarch64/aarch64-simd.md (xor<mode>3<vczle><vczbe>): Use
	'De' constraint.
	* config/aarch64/constraints.md (De): Add new constraint.

gcc/testsuite/ChangeLog:
	PR target/117292
	* gcc.target/aarch64/sve/single_5.c: Remove xfails.
	* gcc.target/aarch64/pr117292.c: New test.