[Bug] 73581 number_format allows for -0.00

[duncan3dc]

• Added a test for Bug 73581
• Attempted a fix by re-checking if a number is negative after it's been rounded

[KalleZ]

Seems reasonable tbh, but since it can have edge cast effects you might want to run it by internals, also remember to update UPGRADING since this is most likely to only go in master

[duncan3dc]

Thanks @KalleZ, will do 👍

[php-pulls]

Comment on behalf of krakjoe at php.net:

labelling

[smalyshev]

I think we need to be very careful in changing number formatting functions. Especially given that many other languages produce the same result: http://news.php.net/php.internals/97186

[krakjoe]

Having read the internals conversation, I'm closing this PR.

We must not deviate from IEEE 754.