[CodeCompletion] Don't restore the parser position after the second pass

This is just not necessary. This parser lives only for the single second
pass.

Author: rintaro

lib/Parse/Parser.cpp

@@ -143,17 +143,8 @@ void Parser::performCodeCompletionSecondPassImpl(
   // Disable libSyntax creation in the delayed parsing.
   SyntaxContext->disable();
 
-  auto BeginParserPosition = getParserPosition(info.BodyPos);
-
-  // ParserPositionRAII needs a primed parser to restore to.
-  if (Tok.is(tok::NUM_TOKENS))
-    consumeTokenWithoutFeedingReceiver();
-
-  // Ensure that we restore the parser state at exit.
-  ParserPositionRAII PPR(*this);
-
-  // Rewind to the beginning of the top-level code.
-  restoreParserPosition(BeginParserPosition);
+  // Set the parser position to the start of the delayed decl or the body.
+  restoreParserPosition(getParserPosition(info.BodyPos));
 
   // Do not delay parsing in the second pass.
   llvm::SaveAndRestore<bool> DisableDelayedBody(DelayBodyParsing, false);