From Vassil and me: move RAII out of ParseWithShortcuts().

The RAII destructs TemplateIdAnnotations that are still needed by the caller, as pointed out by valgrind:
==4595== Invalid read of size 4
==4595==    at 0x1C88E9A: clang::Sema::DecomposeUnqualifiedId(clang::UnqualifiedId const&, clang::TemplateArgumentListInfo&, clang::DeclarationNameInfo&, clang::TemplateArgumentListInfo const*&) (SemaExpr.cpp:1635)
==4595==    by 0x147FF03: clang::FunctionDecl const* cling::findFunction<clang::FunctionDecl const*>(clang::DeclContext*, clang::CXXScopeSpec&, llvm::StringRef, llvm::SmallVector<clang::Expr*, 4u> const&, bool, clang::ASTContext&, clang::Parser&, clang::Sema&, clang::FunctionDecl const* (*)(clang::DeclContext*, bool, llvm::SmallVector<clang::Expr*, 4u> const&, clang::LookupResult&, clang::DeclarationNameInfo&, clang::TemplateArgumentListInfo const*, clang::ASTContext&, clang::Parser&, clang::Sema&)) (LookupHelper.cpp:819)
==4595==    by 0x147DE1A: cling::LookupHelper::findFunctionArgs(clang::Decl const*, llvm::StringRef, llvm::StringRef, bool) const (LookupHelper.cpp:1374)
==4595==  Address 0x8013e74 is 68 bytes inside a block of size 136 free'd
==4595==    at 0x402B77D: free (vg_replace_malloc.c:468)
==4595==    by 0x1484A11: clang::TemplateIdAnnotation::Destroy() (ParsedTemplate.h:205)
==4595==    by 0x1484979: clang::DestroyTemplateIdAnnotationsRAIIObj::~DestroyTemplateIdAnnotationsRAIIObj() (RAIIObjectsForParser.h:446)
==4595==    by 0x1484914: clang::DestroyTemplateIdAnnotationsRAIIObj::~DestroyTemplateIdAnnotationsRAIIObj() (RAIIObjectsForParser.h:442)
==4595==    by 0x14848F8: cling::ParserStateRAII::~ParserStateRAII() (LookupHelper.cpp:67)
==4595==    by 0x147F284: cling::ParserStateRAII::~ParserStateRAII() (LookupHelper.cpp:54)
==4595==    by 0x147EDB1: cling::ParseWithShortcuts(clang::DeclContext*, clang::CXXScopeSpec&, llvm::StringRef, clang::Parser&, clang::Sema&, clang::UnqualifiedId&) (LookupHelper.cpp:765)
==4595==    by 0x147FE5A: clang::FunctionDecl const* cling::findFunction<clang::FunctionDecl const*>(clang::DeclContext*, clang::CXXScopeSpec&, llvm::StringRef, llvm::SmallVector<clang::Expr*, 4u> const&, bool, clang::ASTContext&, clang::Parser&, clang::Sema&, clang::FunctionDecl const* (*)(clang::DeclContext*, bool, llvm::SmallVector<clang::Expr*, 4u> const&, clang::LookupResult&, clang::DeclarationNameInfo&, clang::TemplateArgumentListInfo const*, clang::ASTContext&, clang::Parser&, clang::Sema&)) (LookupHelper.cpp:801)
==4595==    by 0x147DE1A: cling::LookupHelper::findFunctionArgs(clang::Decl const*, llvm::StringRef, llvm::StringRef, bool) const (LookupHelper.cpp:1374)