fixes #18233, #18235 - isolate pagelets state between tests
Moves pagelets state into instances of Pagelets::Manager with clearer dup semantics, and allows the instance to be backed up and restored around tests using the PageletsIsolation test case mixin.
fixes #18233, #18235 - isolate pagelets state between tests
Moves pagelets state into instances of Pagelets::Manager with clearer
dup semantics, and allows the instance to be backed up and restored
around tests using the PageletsIsolation test case mixin.