build: prepare for TypeScript 3.9 (#36989)

- Fix several compilation errors
- Update @microsoft/api-extractor to be compatible with TypeScript 3.9

PR Close #36989

modules/benchmarks/src/util.ts

@@ -41,7 +41,8 @@ export function bindAction(selector: string, callback: () => void) {
 
 export function profile(create: () => void, destroy: () => void, name: string) {
   return function() {
-    window.console.profile(name);
+    // 'console.profile' is experimental and was removed from DOM lib in TS 3.9
+    (window.console as any).profile(name);
     const noOfRuns = 150;
     let durations: number[] = [];
     let count = 0;
@@ -52,7 +53,8 @@ export function profile(create: () => void, destroy: () => void, name: string) {
       durations.push(end);
       destroy();
     }
-    window.console.profileEnd();
+    // 'console.profileEnd' is experimental and was removed from DOM lib in TS 3.9
+    (window.console as any).profileEnd();
     reportProfileResults(durations, noOfRuns);
   };
 }