Rewrite 7.b.i and 7.b.ii to not overflow integer range

[sno2]

The current steps use a unique way of checking for overflows:

i. Set count to count + 1. ii. If count ≥ 2**53, then (...)

This compares count to a value outside of the valid integer range. I believe the spec has explicitly avoided defining comparisons with integer outside of the range as shown in the following examples:

• https://tc39.es/ecma262/#sec-groupby (See 6.a)
• https://tc39.es/ecma262/#sec-number.issafeinteger (See 1.a)
• https://tc39.es/ecma262/#sec-advancestringindex (See 1)
• https://tc39.es/ecma262/#sec-array.from (See 5.e.i)
• https://tc39.es/ecma262/#sec-array.prototype.concat (5.b.ii)
• ... a few more usages of 2**53 - 1

I think it would be better to swap these instructions with this:

i. If count >= 2**53 - 1, then (...) ii. Set count to count + 1.

which would avoid a value of count outside of the integer range. Thanks for the proposal.

[sno2]

Would this change be better as a PR?