cntlz is the old POWER mnemonic.
cntlzw is the PowerPC mnemonic.
This change fixes an issue when -no-integrated-as.
The opcode cntlz is unrecognized by gas
Change PowerPC tests to reflect the insn change from cntlz to cntlzw.
Alias the POWER mnemonic cntlz[.] to the PowerPC mnemonic cntlzw[.]
This is done for because the POWER cntlz mnemonic has be used in llvm for
a very long time. We need to make sure that assembly programs
that are using the cntlz[.] do not break with this change.
Add assembly test to verify cntlz[.] is encoded correctly.