AArch64 testsuite: Force shrn-combine-*.c to use NEON.

AArch64 testsuite: Force shrn-combine-*.c to use NEON.

These tests are testing Advanced SIMD codegen, so if the compiler or the
testsuite is forcing SVE they will fail.

This adds +nosve so that we always generate Advanced SIMD codegen.

gcc/testsuite/ChangeLog:

	PR target/102907
	* gcc.target/aarch64/shrn-combine-1.c: Disable SVE.
	* gcc.target/aarch64/shrn-combine-2.c: Likewise.
	* gcc.target/aarch64/shrn-combine-3.c: Likewise.
	* gcc.target/aarch64/shrn-combine-4.c: Likewise.
	* gcc.target/aarch64/shrn-combine-5.c: Likewise.
	* gcc.target/aarch64/shrn-combine-6.c: Likewise.
	* gcc.target/aarch64/shrn-combine-7.c: Likewise.