Use the default method CC in GetFullTypeForDeclarator.

Before this patch explicit template instatiations of member function templates
were failing with the microsoft abi and 32 bits. This was happening because
the expected and computed function types had different calling conventions.

This patch fixes it by considering the default calling convention in
GetFullTypeForDeclarator.

This fixes pr17973.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@195032 91177308-0d34-0410-b5e6-96231b3b80d8
The code using the StmtPrinterHelper object failed to account for a null object in many cases, which could have led to crashes were it ever to be null. Now passing the object by reference instead of by pointer because it is never null in practice. No functional changes intended.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@195043 91177308-0d34-0410-b5e6-96231b3b80d8