Sum of an array constructor containing an implied DO loop doesn't compile

[JeanVezina]

Sample reproducer

`program expr2
implicit none
integer i
print *,sum([(i,i=1,100)])
end program

`

[certik]

Good catch, it doesn't work with WASM yet. It works with our LLVM backend:

$ lfortran a.f90
5050

But we need to fix the WASM backend also for this case. We plan to do this after we reach beta.