[Inspector] Don't catch throwable on toString calls for inspector.

An additional wpt test (console-label-conversion.any.js) verifies that
calling toString will cause exception propagation.
Remove the TryCatch block.

BUG=chromium:948257
R=dgozman@chromium.org

Change-Id: Idaaf264b7675f7df8ead128c085ac4d4c044005d
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1579541
Commit-Queue: Dave Tapuska <dtapuska@chromium.org>
Reviewed-by: Dmitry Gozman <dgozman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#61023}

src/inspector/v8-console.cc

@@ -124,7 +124,6 @@ class ConsoleHelper {
       return defaultValue;
     }
     v8::Local<v8::String> titleValue;
-    v8::TryCatch tryCatch(m_context->GetIsolate());
     if (!m_info[0]->ToString(m_context).ToLocal(&titleValue))
       return defaultValue;
     return toProtocolString(m_context->GetIsolate(), titleValue);