[torque-ls] Fix Json serialization

Stringification of Json wrongly used quotes for "true", "false" and
"null".

Drive-by: Manually flush std::cout when sending messages. This might
fix the server on windows.

R=tebbi@chromium.org

Bug: v8:8880
Change-Id: Ie499595a1b429514c5d8b1d3ece24f4690ece02e
Reviewed-on: https://chromium-review.googlesource.com/c/1498132Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Commit-Queue: Simon Zünd <szuend@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59992}

src/torque/ls/json.cc

@@ -24,10 +24,10 @@ void SerializeToString(std::stringstream& str, const JsonValue& value) {
       str << StringLiteralQuote(value.ToString());
       break;
     case JsonValue::IS_NULL:
-      str << "\"null\"";
+      str << "null";
       break;
     case JsonValue::BOOL:
-      str << (value.ToBool() ? "\"true\"" : "\"false\"");
+      str << (value.ToBool() ? "true" : "false");
       break;
     case JsonValue::OBJECT: {
       str << "{";

src/torque/ls/message-handler.cc

@@ -54,7 +54,7 @@ void WriteMessage(JsonValue& message) {
   Logger::Log("[outgoing] ", content, "\n\n");
 
   std::cout << kContentLength << content.size() << "\r\n\r\n";
-  std::cout << content;
+  std::cout << content << std::flush;
 }
 
 namespace {