Migrates PersistenceImpl.test.ts to use the full TestUniverse helper
class instead of describeWithEnvironment or global singletons.

Bug: 493763857
Change-Id: I2fb3ab2ba9d4d4612cf7c2bd611bb7bb2d06bf58
TAG=agy
CONV=731b49dc-e99e-41d0-88ba-37dfd59a7ed3
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/8051345
Auto-Submit: Simon Zünd <szuend@chromium.org>
Commit-Queue: Kim-Anh Tran <kimanh@chromium.org>
Reviewed-by: Kim-Anh Tran <kimanh@chromium.org>
Commit-Queue: Simon Zünd <szuend@chromium.org>