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.

gcc/testsuite/gcc.target/i386/pr104637.c

@@ -1,5 +1,5 @@
-/* { dg-do compile } */
-/* { dg-options "-Og -fno-forward-propagate -mavx" } */
+/* { dg-do compile { target { ! ia32 } } } */
+/* { dg-options "-Og -fno-forward-propagate -mavx -Wno-div-by-zero" } */
 
 typedef short __attribute__((__vector_size__ (64))) U;
 typedef unsigned long long __attribute__((__vector_size__ (32))) V;
@@ -13,7 +13,7 @@ void
 foo (char a, char b, _Complex char c, V v)
 {
   u = (U) { u[0] / 0, u[1] / 0, u[2] / 0, u[3] / 0, u[4] / 0, u[5] / 0, u[6] / 0, u[7] / 0,
-	    u[8] / 0, u[0] / 0, u[9] / 0, u[10] / 0, u[11] / 0, u[12] / 0, u[13] / 0, u[14] / 0, u[15] / 0,
+	    u[8] / 0, u[9] / 0, u[10] / 0, u[11] / 0, u[12] / 0, u[13] / 0, u[14] / 0, u[15] / 0,
 	    u[16] / 0, u[17] / 0, u[18] / 0, u[19] / 0, u[20] / 0, u[21] / 0, u[22] / 0, u[23] / 0,
 	    u[24] / 0, u[25] / 0, u[26] / 0, u[27] / 0, u[28] / 0, u[29] / 0, u[30] / 0, u[31] / 0 };
   c += i;