aarch64: Fix bug with max/min (PR116934)

aarch64: Fix bug with max/min (PR116934)

In ac4cdf5cb43c0b09e81760e2a1902ceebcf1a135, I introduced a bug where
I put the new unspecs, UNSPEC_COND_SMAX and UNSPEC_COND_SMIN, into the
wrong iterator.

I should have put new unspecs in SVE_COND_FP_MAXMIN but I put it in
SVE_COND_FP_BINARY_REG instead. That was incorrect because the
SVE_COND_FP_MAXMIN iterator is being used for predicated floating-point
maximum/minimum, not SVE_COND_FP_BINARY_REG.

Also added a testcase to validate the new change.

Regression tested on aarch64-unknown-linux-gnu and found no regressions.
There are some test cases with "libitm" in their directory names which
appear in compare_tests output as changed tests but it looks like they
are in the output just because of changed build directories, like from
build-patched/aarch64-unknown-linux-gnu/./libitm/* to
build-pristine/aarch64-unknown-linux-gnu/./libitm/*. I didn't think it
was a cause of concern and have pushed this for review.

gcc/ChangeLog:

	PR target/116934
	* config/aarch64/iterators.md: Move UNSPEC_COND_SMAX and
	UNSPEC_COND_SMIN to correct iterators.

gcc/testsuite/ChangeLog:

	PR target/116934
	* gcc.target/aarch64/sve2/pr116934.c: New test.