Remove PID-log line

Author: weswigham

src/testRunner/externalCompileRunner.ts

@@ -185,7 +185,9 @@ function stripRushStageNumbers(result: string): string {
  * so we purge as much of the gulp output as we can
  */
 function sanitizeUnimportantGulpOutput(result: string): string {
-    return result.replace(/^.*(\] (Starting)|(Finished)).*$/gm, "").replace(/\n+/g, "\n");
+    return result.replace(/^.*(\] (Starting)|(Finished)).*$/gm, "") // task start/end messages (nondeterministic order)
+        .replace(/^.*\] Respawned to PID: \d+.*$/gm, "") // PID of child is OS and system-load dependent (likely stableish in a container but still dangerous)
+        .replace(/\n+/g, "\n");
 }
 
 function sanitizeTimestamps(result: string): string {

tests/baselines/reference/docker/vscode.log

@@ -3,7 +3,6 @@ Standard output:
 yarn run vX.X.X
 $ gulp compile --max_old_space_size=4095
 [XX:XX:XX] Node flags detected: --max_old_space_size=4095
-[XX:XX:XX] Respawned to PID: 29
 [XX:XX:XX] Using gulpfile /vscode/gulpfile.js
 [XX:XX:XX] Error: /vscode/src/vs/workbench/browser/parts/titlebar/titlebarPart.ts(560,5): Type 'null' is not assignable to type 'string'.
 [XX:XX:XX] Error: /vscode/src/vs/base/browser/ui/menu/menubar.ts(742,7): Type '"underline" | null' is not assignable to type 'string'.