Pressing Stop Script doesn't actually stop the script when running on Android devices via IDE

**Describe the bug**
When I try to stop a script, I press the stop button at the top of the toolbar. The execution of the script inside the editor stops and the logger prints that the script was manually stopped BUT it doesn't stop.

The script continues to run on the device unless I completely kill all the `AirtestIDE` processes or remove and then re-attach the device.

It feels like every time I start a script a new thread is created, and that thread isn't properly disposed of when I press stop.

**To Reproduce**
Steps to reproduce the behavior:
1. Run script on a real device
2. stop script
3. watch it continue

**Expected behavior**
Scripts should stop when the stop button is pressed.

**Screenshots**
If applicable, add screenshots to help explain your problem.

**python version:** `python3.6.5`

**airtest version:** `1.1.3`

**Smartphone (please complete the following information):**
- Device: Google Pixel 3
- OS: Latest Android

- Samsung Galaxy S5
- Last supported OS

- Galaxy Tab
- Latest OS supported