Internal Compiler Error when compiling arithmetic if code with -i8 flag

[kiranchandramohan]

Code with arithmetic if when compiled using the -i8 flag shows an internal compiler error.
F90-F-0000-Internal compiler error. addili: illegal IL_TYPE(opc) 0

IF (J) 85,85,105
85 I = J
105 I = J
END 

This is a regression introduced (a4012a9) when adding half-precision support. The issue happens because the aif array size was increased from 4 to 5 and the index for integer8 increased from 3 to 4 but the entry for half-precision was not added. Hence the index for integer8 pointing to an incorrect location.
Relevant file: tools/flang2/flang2exe/exp_ftn.cpp

Is the correct fix to

1. Add the entry for half precision. Currently not able to test it since parser does not seem to be taking in real*2.
   or
2. Revert to the original array size and index for integer*8.

I can make Pull Requests for both 1 and 2 if necessary.