[ASTImporter] Add support to import some AST nodes:

* CXXOperatorCallExpr
* SizeOfPackExpr
* DependentTemplateSpecializationType
* DependentSizedArray
* CXXTypeidExpr
* Fix importing CXXTemporaryObjectExpr

Some of the changes are based on
https://github.com/haoNoQ/clang/blob/summary-ipa-draft/lib/AST/ASTImporter.cpp

Differential Revision: https://reviews.llvm.org/D42335

llvm-svn: 323589