[AArch64] Fix reversed vcond_mask invocation in aarch64_evpc_sel

[AArch64] Fix reversed vcond_mask invocation in aarch64_evpc_sel

aarch64_evpc_sel (new in GCC 10) got the true and false vectors
the wrong way round, leading to execution failures with fixed-length
128-bit SVE.

Now that the ACLE types are in trunk, it's much easier to match
the exact asm sequence for a permute.

2020-01-10  Richard Sandiford  <richard.sandiford@arm.com>

gcc/
	* config/aarch64/aarch64.c (aarch64_evpc_sel): Fix gen_vcond_mask
	invocation.

gcc/testsuite/
	* gcc.target/aarch64/sve/sel_1.c: Use SVE types for the arguments and
	return values.  Use check-function-bodies instead of scan-assembler.
	* gcc.target/aarch64/sve/sel_2.c: Likewise
	* gcc.target/aarch64/sve/sel_3.c: Likewise.

From-SVN: r280121