testsuite: arm: Use effective-target for vect-early-break-cbranch test

Update test cases to use -mcpu=unset/-march=unset feature introduced in
r15-3606-g7d6c6a0d15c.

gcc/testsuite/ChangeLog:

	* gcc.target/arm/vect-early-break-cbranch.c: Use
	effective-target arm_arch_v8a_hard.

Signed-off-by: Torbjörn SVENSSON <torbjorn.svensson@foss.st.com>

gcc/testsuite/gcc.target/arm/vect-early-break-cbranch.c

 /* { dg-do compile } */
 /* { dg-require-effective-target vect_early_break } */
-/* { dg-require-effective-target arm_neon_ok } */
-/* { dg-require-effective-target arm32 } */
-/* { dg-options "-O3 -march=armv8-a+simd -mfpu=auto -mfloat-abi=hard  -fno-schedule-insns -fno-reorder-blocks -fno-schedule-insns2" } */
+/* { dg-require-effective-target arm_arch_v8a_hard_ok } */
+/* { dg-options "-O3 -fno-schedule-insns -fno-reorder-blocks -fno-schedule-insns2" } */
+/* { dg-add-options arm_arch_v8a_hard } */
 /* { dg-final { check-function-bodies "**" "" "" } } */
 
 #define N 640