Add support for frameless function compact unwind encodings on x86_64/i386. This completes the compact unwind support for x86 targets.  
Add support for frameless function compact unwind encodings on x86_64/i386.
This completes the compact unwind support for x86 targets.  

I'm still skipping the UNWIND_X86_64_MODE_STACK_IND encodings for
x86_64 right now because clang was emitting bad data for this form
until it was fixed in r217020 circa Sep 2014.

arm64 parsing still needs to be added.



git-svn-id: 4c4cc70b1ef44ba2b7963015e681894188cea27e@224698 91177308-0d34-0410-b5e6-96231b3b80d8

apple/swift-lldb,apple/swift-lldb,apple/swift-lldb,apple/swift-lldb,llvm-mirror/lldb,llvm-mirror/lldb,apple/swift-lldb,llvm-mirror/lldb,llvm-mirror/lldb,apple/swift-lldb,llvm-mirror/lldb