[PowerPC][HTM]Fix $zero is not a GPRC register for builtin_ttest
This was found during HTM cleanup.
Adding a test for builtin_ttest would expose following issue.
*** Bad machine code: Illegal physical register for instruction ***
- function: test10
- basic block: %bb.0 entry (0xf0e57497b58)
- instruction: %5:crrc0 = TABORTWCI 0, $zero, 0
- operand 2: $zero
$zero is not a GPRC register.
LLVM ERROR: Found 1 machine code errors.
Differential Revision: https://reviews.llvm.org/D63079
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@362974
91177308-0d34-0410-b5e6-
96231b3b80d8