[Bug-apl] Segfault in 5⎕CR and 6⎕CR

[Kacper Gutowski]

Dyadic ⎕CR with 5 or 6 as its left argument and character scalar
instead of vector as right causes segmentation fault:

      5⎕CR '1'


====================================================
SEGMENTATION FAULT

----------------------------------------
-- Stack trace at main.cc:63
----------------------------------------
0x7f84a772d610 __libc_start_main
0x444205  main
0x57c01d   Workspace::immediate_execution(bool)
0x48cd1a    Command::process_line()
0x48cdda     Command::do_APL_expression(UCS_string&)
0x497df5      Executable::execute_body() const
0x5275f0       StateIndicator::run()
0x4cd5d8        Prefix::reduce_statements()
0x4c87a5         Prefix::reduce_A_F_B_()
0x500374          Quad_CR::eval_AB(Value_P, Value_P)
0x4fdbf7           Quad_CR::do_CR(long, Value const&, PrintContext)
0x7f84a8568d30
0x449217
========================================
====================================================

Goodbye.


Interestingly, with each operator it reports WS FULL:

      5⎕CR¨'1'
WS FULL
      5 ⎕CR¨'1'
      ^    ^

-k