allow implicit target type deduction

[kasperk81]

foreach (var n in [1,2,3]) rightfully throws error CS9176: There is no target type for the collection expression. and expects (int[]) cast.

compiler should at least be able to deduce int[] implicitly when type is specified foreach (int n in [1,2,3])?

[HaloFour]

See: #7913

For a for loop I would hope that the compiler can be smart enough to elide allocations, so not even int[].