func_get_args() should be cast to variable before being modified

[boonebgorges]

The behavior of func_get_args() was changed in PHP 7.0, so that it reflects the current value of function params, rather than the values originally passed. In cases where we use func_get_args(), intending to reference the original values, we should cast to a variable early in the function. See ​https://www.php.net/manual/en/migration70.incompatible.php#migration70.incompatible.other.func-parameter-modified

[boonebgorges]

In 12426:

Cast func_get_args() to variable early in class methods.

Since PHP 7.0, calling func_get_args() returns the current value of
the parameter, which may have been modified since the beginning of the
method. By storing the original function arguments in a variable at the
beginning of the method, we ensure that the value operated on later in
the method accurately reflects what was originally passed.

In most cases addressed by this changeset, there was no real-world
possibility that the arguments could be changed; we make this change
mostly as a best practice, and to appease the PHP compatibility linter.

Fixes #8125.