testsuite: Fix up pr104637 testcase [PR104637]

testsuite: Fix up pr104637 testcase [PR104637]

This testcase FAILs everywhere for 3 reasons:
1) the testcase can't work on ia32, where sizeof (long double) == 12
   and as it is not a power of 2, we disallow creating vectors with such
   elements, -mx32 and -m64 are fine
2) the testcase emits a lot of -Wdiv-by-zero warnings, I've just added
   -Wno-div-by-zero to dg-options
3) my fault, when tweaking the testcase I've missed 33 initializers of
   a 32 element vector which didn't change anything on the ICE, but is
   still reported

This patch fixes all of it, tested with
RUNTESTFLAGS='--target_board=unix\{-m32,-m64\} i386.exp=pr104637.c'
both without the LRA fix where it ICEs and with it where it passes
everywhere.

2022-03-02  Jakub Jelinek  <jakub@redhat.com>

	PR rtl-optimization/104637
	* gcc.target/i386/pr104637.c: Don't run on ia32.  Add -Wno-div-by-zero
	to dg-options.
	(foo): Remove extraneous initializer.