chore: fail build if a command from tsc-watch fails.

This bug was introduced with eba6e7946d
to integrate the compiler_cli into the build properly.

Closes #8480

tools/tsc-watch/index.ts

@@ -103,8 +103,8 @@ if (platform == 'node') {
 
 if (runMode === 'watch') {
   tscWatch.watch();
-} else if (runMode === 'triggerCmds') {
-  tscWatch.triggerCmds();
+} else if (runMode === 'runCmdsOnly') {
+  tscWatch.runCmdsOnly();
 } else {
   tscWatch.run();
 }

tools/tsc-watch/tsc_watch.ts

@@ -81,6 +81,11 @@ export class TscWatch {
     this.watch();
   }
 
+  runCmdsOnly() {
+    this.runOnce = true;
+    this.triggerCmds();
+  }
+
   consumeLine(buffer: Buffer, isStdError: boolean) {
     var line = '' + buffer;
     if (contains(line, this.start)) {