flang compiler if statement crashes with 8-byte integers

[nikhil-mk]

The following test fails in flang :

subroutine test()
       integer n2
       n2=10
       if (n2) 10,20,20
10 write(6,)'10'
       return
20 write(6,)'20'
       end

error:
F90-F-0000-Internal compiler error. addili: illegal IL_TYPE(opc) 0 (test.f: 4)

Pull request #859 fixes this
@gklimowicz @sscalpone