When we attach to a frame, we send a call to get
the page frame tree from CDP. Based on the tree data
we look up the parent frame if parentId is provided.
The problem is that the call to get the page frame
tree could take arbitrary time and the calls for the
parent and child frames might happen at the same time.
So the situation where the frame tree for the child frame
is resolved before the parent frame is known is fairly
common.
This PR addresses the issue by awaiting for the parent
frame id before attempting to register a child frame.
* The testing tsconfig.json inherits from the base TS config.
* A lot of type assertions have been inserted...a lot.
* All testing utilities have migrated to TS.
* text-diff is being replaced with diff for TS compatibility.
* ProtocolError has been added to PuppeteerErrors and PuppeteerErrors is no longer a record (it's been frozen).
* Fixes a small bug where null was an allowable media type in emulation (should be undefined).
