Remove a tracing macro with a dangling pointer (#11002)

Fixes https://github.com/flutter/flutter/issues/38543

third_party/txt/src/txt/font_collection.cc

@@ -231,8 +231,6 @@ std::shared_ptr<minikin::FontFamily> FontCollection::CreateMinikinFontFamily(
     minikin_fonts.emplace_back(std::move(minikin_font));
   }
 
-  TRACE_EVENT1("flutter", "minikin::FontFamily", "MinikinFontsCount",
-               std::to_string(minikin_fonts.size()).c_str());
   return std::make_shared<minikin::FontFamily>(std::move(minikin_fonts));
 }