GeezerVison

Fixes #1735

Array.prototype.includes uses SameValueZero, so [1, NaN, 3].includes(NaN) is true in JS. __TS__ArrayIncludes compared each element with ==, and NaN == NaN is always false in Lua, so it returned false.

The lualib now checks once whether the search value is NaN (searchElement !== searchElement, same trick as __TS__NumberIsNaN) and, if so, also matches an element that is not equal to itself. For any other search value the loop does the same == check as before. The generated Lua stays a plain loop:

local searchingForNaN = searchElement ~= searchElement
for i = k + 1, len do
    local element = self[i]
    if element == searchElement or searchingForNaN and element ~= element then
        return true
    end
end

Tests: added [1, NaN, 3].includes(NaN) (fails before, passes after) and [1, 2, 3].includes(NaN) to the array.includes cases in test/unit/builtins/array.spec.ts. npm run lint and the full jest run pass.