chore(benchmark): remove trailing whitespace in benchmark.json

Drop stray trailing space after the evalConfig closing brace so the
benchmark config JSON is cleanly formatted.

Co-authored-by: Cursor <cursoragent@cursor.com>

test/benchmark/benchmark.json

@@ -15,5 +15,5 @@
       "EscapeSequenceParser.benchmark.js.*.averageRuntime",
       "Terminal.benchmark.js.*.averageRuntime"
     ]
-  } 
+  }
 }