Re-land parsing and printing for Clang function types.

This reverts commit e805fe486e, which reverted
the change earlier. The problem was caused due to a simultaneous change to some
code by the PR with parsing and printing for Clang function types (#28737)
and the PR which introduced Located<T> (#28643).

This commit also includes a small change to make sure the intersecting region
is fixed: the change is limited to using the fields of Located<T> in the
`tryParseClangType` lambda.

lib/Frontend/ModuleInterfaceSupport.cpp

@@ -440,7 +440,7 @@ bool swift::emitSwiftInterface(raw_ostream &out,
   printImports(out, M);
 
   const PrintOptions printOptions = PrintOptions::printSwiftInterfaceFile(
-      Opts.PreserveTypesAsWritten);
+      Opts.PreserveTypesAsWritten, Opts.PrintFullConvention);
   InheritedProtocolCollector::PerTypeMap inheritedProtocolMap;
 
   SmallVector<Decl *, 16> topLevelDecls;