The hash is used to check whether the arginfo file needs to be
regenerated. PHP-Parser will only be downloaded if this is actually
necessary.
This ensures that release artifacts will never try to regenerate
stubs and thus fetch PHP-Parser, as long as you do not modify any
files.
Closes GH-5739.
`bcdiv()` and `bcmod()` throw DivisionByZeroError if the divisor is 0,
which matches the behavior of the `/` and `%` operators, and `bcsqrt()`
throws ValueError for negative operands.