D105263 changed this test to not expect a MachineVerifier error on this
instruction:
; FP16 reg is sub_reg of xmm
%0:_(s16) = COPY $xmm0
D107082 changed the behaviour back again so that this instruction did
cause an error, but the test was not updated to expect the error.
Differential Revision: https://reviews.llvm.org/D148534