MIPS32: Don't leave vector registers in an unpredictable state

Don't use regular FPU instructions in the Vectorizer because some
of those (such as mtc1 and mthc1) may leave remaining elements in
an unpredictable state.

Test: ./testrunner --optimizing --target --32 in QEMU (MIPS32R6)
Change-Id: I9b082bfd83360374b2f4831ef5f5bd35b00272a5
1 file changed