Handle the remaining known issues (modulo snan) with the double/single parsing logic...

Handle the remaining known issues (modulo snan) with the double/single parsing logic (#21036)

* Fixing the double/single parser to return negative zero for `-0`

* Updating the Utf8Parser to allow exponents of arbitrary length

* Updating the double/single parser to support case-insensitive and signed infinity/nan

* Ensure TryParseAsSpecialFloatingPoint handles the case where we have an empty source

* Fixing the number parser to allow `-0` for decimal and to not parse '++infini'