fix: Race condition on execution when context closes

Accessing ProcessState on non-linux operating systems immediately
after context cancels can conflict with the Wait() stdlib func:
https://github.com/golang/go/blob/36b81acfa19d9fedf6a0cd60c394fd7a7703834e/src/os/exec/exec.go#L511

Author: kylecarbs

tfexec/cmd_default.go

@@ -17,7 +17,7 @@ func (tf *Terraform) runTerraformCmd(ctx context.Context, cmd *exec.Cmd) error {
 	go func() {
 		<-ctx.Done()
 		if ctx.Err() == context.DeadlineExceeded || ctx.Err() == context.Canceled {
-			if cmd != nil && cmd.Process != nil && cmd.ProcessState != nil {
+			if cmd != nil && cmd.Process != nil {
 				err := cmd.Process.Kill()
 				if err != nil {
 					tf.logger.Printf("error from kill: %s", err)