Do not attempt to kill the process if it has already exited (#22424)

Closes #22420

This bugs seems to have existed every since `rawProcessApi.ts` was
created. `proc.killed` can be `false` even after process has exited.

src/client/common/process/rawProcessApis.ts

@@ -75,10 +75,21 @@ export function shellExec(
  resolve({ stderr: stderr && stderr.length > 0 ? stderr : undefined, stdout });
  }
  };
+ let procExited = false;
  const proc = exec(command, shellOptions, callback); // NOSONAR
+ proc.once('close', () => {
+ procExited = true;
+ });
+ proc.once('exit', () => {
+ procExited = true;
+ });
+ proc.once('error', () => {
+ procExited = true;
+ });
  const disposable: IDisposable = {
  dispose: () => {
- if (!proc.killed) {
+ // If process has not exited nor killed, force kill it.
+ if (!procExited && !proc.killed) {
  if (proc.pid) {
  killPid(proc.pid);
  } else {
@@ -114,7 +125,8 @@ export function plainExec(
  const deferred = createDeferred<ExecutionResult<string>>();
  const disposable: IDisposable = {
  dispose: () => {
- if (!proc.killed) {
+ // If process has not exited nor killed, force kill it.
+ if (!proc.killed && !deferred.completed) {
  if (proc.pid) {
  killPid(proc.pid);
  } else {