[platform] ignore SIGHUP in restarter script (IDEA-162263)

When the IDE is launched in it's own terminal (File Manager | Run in Terminal), shutting it down kills the restarter script as well. Ignoring the signal allows the script to outlive a terminal and successfully restart the IDE.

bin/linux/restart.py

@@ -3,12 +3,15 @@
 # Waits for the parent process to terminate, then executes specified commands.
 
 import os
+import signal
 import sys
 import time
 
 if len(sys.argv) < 3:
     raise Exception('usage: restart.py <pid> <path> [optional command]')
 
+signal.signal(signal.SIGHUP, signal.SIG_IGN)
+
 pid = int(sys.argv[1])
 while os.getppid() == pid:
     time.sleep(0.5)