Arm build doesn't print `testfeature` on target-feature test.

[rengolin]

Following PR #1049, there's an error on the Arm builds that are not happening on x86 ones:
#1049 (comment)

error: CPU_FEATURE: expected string not found in input
// CPU_FEATURE: '+testfeature' is not a recognized feature for this target (ignoring feature)

I have reverted just the test (since it's not critical) so we can investigate what the problem is.

@shahidact