Bring the contrib/llvm/patches directory up-to-date.

Bring the contrib/llvm/patches directory up-to-date.

MFC r263892:
Add the llvm/clang patch for r263891.

MFC r264350:
Update the llvm/clang patch for r264345.

MFC r266675:
Add the clang patch for r266674.

MFC r275651:
Add llvm patch corresponding to r275633.

MFC r275747:
Update llvm patches for r274286 and r275633 so all the tests will pass.

MFC r275760:
Add clang patch corresponding to r275759.

MFC r275772:
Update clang patch for r275759 to use correct test cases.

Additionally:
* Remove the clang patch corresponding to r263619, as ARM EABI
  hard-float support was never MFC'd.
* Add clang patch corresponding to r279302.

git-svn-id: svn://svn.freebsd.org/base/stable/10@283015 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f