[libclang] Introduce clang_Cursor_getObjCPropertyAttributes to query the written attributes in a property declaration.

rdar://13684512

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@179803 91177308-0d34-0410-b5e6-96231b3b80d8
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git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@179806 91177308-0d34-0410-b5e6-96231b3b80d8