[mach-o] Update test case to work with latest llvm-objdump output for ARM thumb
code.  Same basic change that was done in r218429 for ARM code.

Where the ARM thumb symbolizer in llvm-objdump’s Mach-O disassembler is now
plumbed in with r221470 from the llvm trunk.
[RegAlloc] Kill off the trivial spiller - nobody is using it any more.