Interrupts are generally ignored in Quote-Quad Input

[mkromberg]

Describe the issue you are having

When waiting for Quote-Quad input, if an interrupt is sent, it is often ignored. Under Windows, it seems to be ignored always. Under Linux, strong interrupts are ignored and weak interrupts seem to take effect after ENTER is pressed.

Did you connect to an already running interpreter or start the interpreter from RIDE?

Started from RIDE.

How do you reproduce the issue?

foo z←⍞ ⎕←⍴z

Paste the contents of Help → About (Shift+F1)

IDE:
  Version: 4.1.3333
  Platform: Win32
  Date: 2018-06-07 11:32:16 +0100
  Git commit: 4ef9f066f2ee49dddbff80f37eeb144995c20e43
  Preferences:{
    "connectFav":"4",
    "kbdLocale":"en_GB",
    "sbar":"0",
    "zoom":"3"
  }

Interpreter:
  Version: 17.0.33947
  Platform: Windows-64
  Edition: Unicode/64
  Date: Aug 13 2018 at 20:17:48

[abrudz]

Awaits #888