[libclang] When initializing an ObjC object via the "[[ClassName alloc] init*]" pattern,
report the 'init*' invocation as non-dynamic via clang_Cursor_isDynamicCall.

Of course it is dynamic at runtime, but for purposes of indexing we can treat as an invocation to ClassName's init*.

Addresses rdar://18916871.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@221641 91177308-0d34-0410-b5e6-96231b3b80d8