[analyzer] Add support for ObjCIndirectCopyRestoreExpr.

Idiomatic objc using ARC will generate this expression regularly due to
NSError out-param passing.  Providing an implementation for this
expression allows the analyzer to explore many more codepaths in ARC
projects.

The current implementation is not perfect but the differences are hopefully
subtle enough to not cause much problems.

rdar://63918914

Differential Revision: https://reviews.llvm.org/D81071