arm: Add new tests for comparison vectorization with Neon and MVE

arm: Add new tests for comparison vectorization with Neon and MVE

This patch mainly adds Neon tests similar to existing MVE ones,
to make sure we do not break Neon when fixing MVE.

mve-vcmp-f32-2.c is similar to mve-vcmp-f32.c but uses a conditional
with 2.0f and 3.0f constants to help scan-assembler-times.

Most of the work of this patch series was carried out while I was
working at STMicroelectronics as a Linaro assignee.

2022-02-22  Christophe Lyon <christophe.lyon@arm.com>

	gcc/testsuite/
	* gcc.target/arm/simd/mve-vcmp-f32-2.c: New.
	* gcc.target/arm/simd/neon-compare-1.c: New.
	* gcc.target/arm/simd/neon-compare-2.c: New.
	* gcc.target/arm/simd/neon-compare-3.c: New.
	* gcc.target/arm/simd/neon-compare-scalar-1.c: New.
	* gcc.target/arm/simd/neon-vcmp-f16.c: New.
	* gcc.target/arm/simd/neon-vcmp-f32-2.c: New.
	* gcc.target/arm/simd/neon-vcmp-f32-3.c: New.
	* gcc.target/arm/simd/neon-vcmp-f32.c: New.
	* gcc.target/arm/simd/neon-vcmp.c: New.