testsuite: i386: Fix gcc.target/i386/pr70321.c on 32-bit Solaris/x86

gcc.target/i386/pr70321.c FAILs on 32-bit Solaris/x86 since its
introduction in

commit 43201f2c
Author: Roger Sayle <roger@nextmovesoftware.com>
Date:   Mon May 30 21:20:09 2022 +0100

    PR target/70321: Split double word equality/inequality after STV on x86.

FAIL: gcc.target/i386/pr70321.c scan-assembler-times mov 1

The failure happens because 32-bit Solaris/x86 defaults to
-fno-omit-frame-pointer.

Fixed by specifying -fomit-frame-pointer explicitly.

Tested on i386-pc-solaris2.11 and i686-pc-linux-gnu.

2024-01-23  Rainer Orth  <ro@CeBiTec.Uni-Bielefeld.DE>

	gcc/testsuite:
	* gcc.target/i386/pr70321.c: Add -fomit-frame-pointer to
	dg-options.