This changes exposes a low-level helper that is used to implement
`forEachArgumentWithParamType` but can also be used without matchers,
e.g. if performance is a concern.
Commit f5ee10538b introduced a copy of the
implementation of the `forEachArgumentWithParamType` matcher that was
needed for optimizing performance of `-Wunsafe-buffer-usage`.
This change shares the code between the two so that we do not repeat
ourselves and any bugfixes or changes will be picked up by both
implementations in the future.
da69eb75cb