[Committed] Add -mno-avx2 to recent gcc.target/i386/xop-vpcmov3.c

[Committed] Add -mno-avx2 to recent gcc.target/i386/xop-vpcmov3.c

Adding -march=cascadelake to the command line options of the recently
added xop-vpcmov3.c test case causes problems as GCC then prefers to
use AVX512's vpternlogd instruction, instead of the XOP vpcmov that
the test is checking for.  This is easily solved by adding an explicit
-mno-avx512vl to the command line options.

Committed to mainline as obvious (in hindsight).

2022-06-08  Roger Sayle  <roger@nextmovesoftware.com>

gcc/testsuite/ChangeLog
	* gcc.target/i386/xop-pcmov3.c: Add -mno-avx512vl to dg-options.