Now that ASTMultiPtr is nothing more than a array reference, make it a MutableArrayRef.

This required changing all get() calls to data() and using the simpler constructors.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@162501 91177308-0d34-0410-b5e6-96231b3b80d8
22 files changed