testsuite: arm: Make arm_neon_ok_nocache consistent with other effective-targets

testsuite: arm: Make arm_neon_ok_nocache consistent with other effective-targets

A recent patch updated arm_neon_ok_nocache with an improved list of
flags to try, but was not consistent with
arm_v8_3a_complex_neon_ok,_nocache arm_v8_2a_fp16_neon_ok_nocache,
arm_v8_3a_fp16_complex_neon_ok_nocache.

This patch inserts "-mcpu=unset -march=armv7-a+simd -mfpu=auto" before
we try to force -mfloat-abi=softfp and -mfloat-abi=hard.

Tested on aarch64-linux-gnu, arm-linux-gnueabihf and several flavors
of arm-none-eabi with non-default configurations.

2026-02-03  Christophe Lyon  <christophe.lyon@arm.com>

	gcc/testsuite/
	* lib/target-supports.exp
	(check_effective_target_arm_neon_ok_nocache): Add "-mcpu=unset
	-march=armv7-a+simd -mfpu=auto" to the list.