Deprecate the two-argument Buffer constructor

The two-argument Buffer constructor could create uninintialized data.
This refactor replaces it with CreateUninitializedWithSizeAndCapacity.

It also refactors the CopyOnWriteBuffer class to use explicit functions when creating uninitialized Buffers.

Also do some checking to ensure that SetData() always has room enough.

Bug: webrtc:42223681
Change-Id: I160c88ca41944c9888d7862e8ce46cd673417a69
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/445040
Auto-Submit: Harald Alvestrand <hta@webrtc.org>
Commit-Queue: Harald Alvestrand <hta@webrtc.org>
Reviewed-by: Danil Chapovalov <danilchap@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#46890}