75d6f508f8
Currently, the interpreter does not initialize `undef` constants of
aggregate types correctly (with respect to arrays).
The initialization of the array elements is skipped although it is valid
to directly write to them. Instructions like
`insertvalue {i32, [4 x i32]} undef, i32 1, 1, 2` therefore lead to a
crash.
This is fixed by initializing array values just as fixed-size vectors or
structs.