[6.x] Fix originalIsEquivalent with floats

[CraigHarley]

According to the PHP Docs:
https://www.php.net/manual/en/language.types.float.php

You shouldn't compare two floats directly for equality.

This only manifests when you cast to a float, otherwise you'll fall into the:

return is_numeric($current) && is_numeric($original)
                && strcmp((string) $current, (string) $original) === 0;

Which works for floats fine.

[BassemN]

I think by using bccomp function, we need to require ext-bcmath into the composer.json file

[CraigHarley]

This project has a depency on: moontoast/math.

So therefore the existence of ext-bcmath is already checked: https://github.com/moontoast/math/blob/master/composer.json#L14

[mfn]

@BassemN is correct though; that another dependency depends on something which is now ultimately a shared dependency is not enough.

This project has a depency on: moontoast/math.

It's only a suggested dependency of illuminate/support.

However you can use illuminate/database independent of Laravel (which I'm doing).

Therefore I believe that the dependency belongs into:

• src/Illuminate/Database/composer.json
  as well as into
• composer.json

Because it's now a hard requirement for Laravel 6.

[GrahamCampbell]

We cannot add that dependency. I'd suggest we change this code to avoid using that function.

[mfn]

lol 😄