testsuite/arm: Fix and rename arm_qbit_ok into arm_sat_ok effective-target
The acle/saturation.c test uses __[su]sat() and
__saturation_occurred() intrinsics but __[su]sat() are defined in
acle.h if __ARM_FEATURE_SAT true, while __saturation_occurred()
depends on __ARM_FEATURE_QBIT.
QBIT is a v5te feature, while SAT is available since v6, so the test
really needs __ARM_FEATURE_SAT, to have both available.
This patch renames arm_qbit_ok into arm_sat_ok and checks
__ARM_FEATURE_SAT. It updates acle/saturation.c accordingly.
This enables the test to pass on arm-eabi with default cpu/fpu/mode,
where arm_qbit previously used -march=armv5te instead of armv6 now.