Frog: Missing check with --enable_type_checks on && and ||

[rakudrama]

This program runs without signalling that isList is not bool on the first iteration.
The VM signals an error.

main() {
  var a = 123;
  var isList = 0;
  for (int i = 0; i < 4000; i++) {
    isList = isList || a is List;
  }
  print('a is List == $isList');
}

The generated code for the assignment is:
isList = $notnull_bool(isList || !!(a && a.is$List));

I would have expected
isList = $notnull_bool(isList) || !!(a && a.is$List);

The placement of the check is even stranger with an expression like

b = b && x > 5 && x < 10;

--->
b = $notnull_bool(b && x > 0) && x < 100;

[jmesserly]

this was a pretty silly bug, it was converting the result of && to bool instead of the arguments. Fix incoming

[jmesserly]

Added Fixed label.