bug 1561697: add mozilla::ipc::WriteIPDLParam to prefix list

[willkg]

This adds mozilla::ipc::WriteIPDLParam to the prefix list so signature generation continues beyond it. By itself, it's too general a bucket. It'd help to know what the T actually is, but that breaks normalization. Continuing to the next frame should clarify the bucket.

[willkg]

Using the example crash report:

app@socorro:/app$ socorro-cmd signature 4fb422eb-61e3-425f-917c-2bb7f0190624
Crash id: 4fb422eb-61e3-425f-917c-2bb7f0190624
Original: mozilla::ipc::WriteIPDLParam<T>
New:      mozilla::ipc::WriteIPDLParam<T> | mozilla::dom::PContentParent::SendWindowPostMessage
Same?:    False

[willkg]

I'm pretty sure this is a step in the right direction. We can always do more later. self-r+