to instruction right after the last instruction in the bundle.
- Add a finalizeBundle() variant that doesn't specify LastMI. Instead, the code
  will find the last instruction in the bundle by following the 'InsideBundle'
  marker. This is useful in case bundles are formed early (i.e. during MI
  scheduling) but finalized later (i.e. after register allocator has finished
  rewriting virtual registers with physical registers).

llvm-svn: 148444