[LLDB][MIPS] MIPS32 branch emulation and single-stepping

    
    SUMMARY:
    This patch implements
      1. Emulation of MIPS32 branch instructions
      2. Enable single-stepping for MIPS32 instructions
      3. Correction in emulation of MIPS64 branch instructions with delay slot
      4. Adjust breakpoint address when breakpoint is hit in a forbidden slot of compact branch instruction
    
    Reviewers: clayborg
    Subscribers: mohit.bhakkad, sagar, bhushan, lldb-commits, emaste, nitesh.jain
    Differential Revision: http://reviews.llvm.org/D10596

llvm-svn: 240373