Merge pull request microsoft#19935 from Microsoft/fixDiagnostics

Fix crash when running tsc with -diagnostics

Author: rbuckton

src/compiler/performance.ts

@@ -10,7 +10,8 @@ namespace ts {
 namespace ts.performance {
     declare const onProfilerEvent: { (markName: string): void; profiler: boolean; };
 
-    const profilerEvent: (markName: string) => void = typeof onProfilerEvent === "function" && onProfilerEvent.profiler === true ? onProfilerEvent : noop;
+    // NOTE: cannot use ts.noop as core.ts loads after this
+    const profilerEvent: (markName: string) => void = typeof onProfilerEvent === "function" && onProfilerEvent.profiler === true ? onProfilerEvent : () => { /*empty*/ };
 
     let enabled = false;
     let profilerStart = 0;