[e2e] Fix and reenable snippets tests
[e2e] Fix and reenable snippets tests

Instead of grabbing the current state of the UI, try and wait for the UI to reach the expected state.

Drive-by: import patched describe, it functions for improved error reporting.

Fixed: 1356139
Change-Id: I6253c382b418db14623b913c44783b69a9912022
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/3921594
Reviewed-by: Kateryna Prokopenko <04b7d4bdbd93555cee90f085bb91b72524d21fca@chromium.org>
Commit-Queue: Philip Pfaffe <639a645feae3653b7aaefa0387217d375f2f82ff@chromium.org>
Auto-Submit: Philip Pfaffe <639a645feae3653b7aaefa0387217d375f2f82ff@chromium.org>

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