More wordsmithing on objc_requires_super documentation.

git-svn-id: http://llvm.org/svn/llvm-project/cfe/trunk@193288 91177308-0d34-0410-b5e6-96231b3b80d8
Implements 64 bit microsoft record layout and adds lit tests to cover 
it.  Also removes all of the microsoft C++ ABI related code from the 
itanium layout builder.

Differential Revision: http://llvm-reviews.chandlerc.com/D2003



git-svn-id: http://llvm.org/svn/llvm-project/cfe/trunk@193290 91177308-0d34-0410-b5e6-96231b3b80d8