[Bug-apl] Quad-EC

[David B. Lamkins]

When used to invoke ⎕FX, ⎕EC returns only the value of executing ⎕FX and not 
any of the values representing the kind of statement executed and its success 
or failure.

      ]boxing 8
      ⎕ec '⎕fx ''foo'''
┌→──┐
│foo│
└───┘
      ⎕ec '⍳3'
┌→──────────────┐
│1 ┌→──┐ ┌→────┐│
│  │0 0│ │1 2 3││
│  └───┘ └─────┘│
└∊──────────────┘