Bug 24457 - X87 FPU Special Purpose Registers

Summary:
  - For 'register read --all' command on x86_64-Linux Platform:

      -- Provide correct values of X87 FPU Special Purpose Registers
      -- Both 32-bit & 64-bit inferiors give correct values on this
         Platform

  - Added a Test Vector:
      -- To verify the expected behaviour of the command

Signed-off-by: Abhishek Aggarwal <abhishek.a.aggarwal@intel.com>

Reviewers: ashok.thirumurthi, granata.enrico, tfiala, clayborg

Differential Revision: http://reviews.llvm.org/D12592

llvm-svn: 246955