[Parser] Add local type declarations to the outermost enclosing source file

The parser is currently responsible for adding local type declarations
to a `SourceFile`, which IR generation later queries. However, IRGen
never sees the source files associated with macro expansion buffers,
so local types introduced there don't get recorded.

In time, this approach of using the parser to record semantic
information should be replaced with something more "pull" oriented.
For now, however, record local type declarations in the outermost
enclosing source file... so we see the ones produced by macro
expansions, too.

Fixes rdar://109370309.

(cherry picked from commit e964d12)

Author: DougGregor

lib/Parse/ParseDecl.cpp

@@ -5100,7 +5100,7 @@ void Parser::recordLocalType(TypeDecl *TD) {
     return;
 
   if (!InInactiveClauseEnvironment)
-    SF.LocalTypeDecls.insert(TD);
+    SF.getOutermostParentSourceFile()->LocalTypeDecls.insert(TD);
 }
 
 /// Set the original declaration in `@differentiable` attributes.

test/Macros/macro_expand.swift

@@ -234,11 +234,17 @@ func testStringifyWithThrows() throws {
 
     // CHECK-DIAGS: @__swiftmacro_9MacroUser23testStringifyWithThrowsyyKF9stringifyfMf1_.swift:1:2: error: call can throw but is not marked with 'try'
 #endif
-  
+
   // The macro adds the 'try' for us.
   _ = #stringifyAndTry(maybeThrowing())
 }
 
+func testStringifyWithLocalType() throws {
+  _ =  #stringify({
+    struct QuailError: Error {}
+    throw QuailError()
+    })
+}
 
 @freestanding(expression) macro addBlocker<T>(_ value: T) -> T = #externalMacro(module: "MacroDefinition", type: "AddBlocker")
 
@@ -495,7 +501,7 @@ func testHasEqualsSelf(
   _ = (y == true) // expected-error{{referencing operator function '=='}}
   _ = (z == true) // expected-error{{referencing operator function '=='}}
   _ = (w == true) // expected-error{{referencing operator function '=='}}
-  #endif
+#endif
 
   // These should be found through the protocol.
   _ = (xP == true)