Add some invalid-decl checks to clang_Type_getOffsetOf.

print-size-type.cpp was checking for specific record layout output for invalid
decls; I've removed the checks but left the records as tests for not crashing.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@184751 91177308-0d34-0410-b5e6-96231b3b80d8
Convert a use of PathV1.h

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@184753 91177308-0d34-0410-b5e6-96231b3b80d8
Check the canonical parameter type with getAs<>() in a static checker

This will prevent breakage when I introduce the DecayedType sugar node.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@184755 91177308-0d34-0410-b5e6-96231b3b80d8