Revert "Split analyzer.cc and change CreateFooGraph methods to free functions"

This reverts commit 68cb390aa5565bcf8a6c360f45177743c701bbda.

Reason for revert: Breaks downstream code.

Original change's description:
> Split analyzer.cc and change CreateFooGraph methods to free functions
>
> Bug: None
> Change-Id: Iaf4a39ad3c9bc681b5ec3f078b328eed0c218942
> Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/446284
> Commit-Queue: Björn Terelius <terelius@webrtc.org>
> Reviewed-by: Rasmus Brandt <brandtr@webrtc.org>
> Cr-Commit-Position: refs/heads/main@{#46891}

Bug: None
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Change-Id: Ie0114c6569c80c6decd4a51c7cb1ea68ab102918
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/448981
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Commit-Queue: Björn Terelius <terelius@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#46892}