testsuite: Remove dg-options from pr100305.c [PR100305]

The test FAILs on i?86-linux (due to -Wpsabi warnings).  But, on closer
inspection it seems there is another problem, the dg-options in the testcase
means that the test is compiled with -O0 -O, -O1 -O, -O2 -O, -O3 -O, -Os -O
etc. options, so effectively is tested multiple times with the same options.

Fixed by dropping the dg-options line, then we have -w by default and iterate
over all the optimization levels (including the -O).

2021-04-29  Jakub Jelinek  <jakub@redhat.com>

	PR target/100305
	* gcc.c-torture/compile/pr100305.c: Remove dg-options.  Add PR line.

gcc/testsuite/gcc.c-torture/compile/pr100305.c

@@ -1,4 +1,4 @@
-/* { dg-options "-O" } */
+/* PR target/100305 */
 
 typedef double v2df __attribute__((vector_size(16)));