Issue Description:

Lazy collection wrappers such as LazyFilterSequence allow indexing into positions that are out of bound, as long as they're in bound for the base collection, and returns the element at the given position in the base collection.

Example from a tweet by @ole:

let evens = Array(1...10)
  .lazy
  .filter { $0.isMultiple(of: 2) }
evens.indices // → [1, 3, 5, 7, 9]
evens[0]      // → 1 (exploding head emoji!)

The correct behaviour should be like that of slices:

let foo = ["a", "b", "c"]
let bar = foo[1...] // Array.SubSequence ["b", "c"]
print(bar[0]) // Fatal error: Index out of bounds