Cache WorkflowIdentifier

[steve-the-edwards]

Looking up the type can cost significantly when repeated. Instead of computing the identifier each time, we cache it.

We do it in a slightly funny way because we want to add this functionality on via a new interface - IdCacheable rather than modifying the core Workflow interface.

The logic that cares about this caching is all in the identifier extension.

[steve-the-edwards]

Update: we are now on 1.7.20 so we can run these tests.

iOS Tests are failing due to old memory manager for Kotlin/Native not liking the modification once the class is capture in the closure related to the changes for caching identifier. We should update to Kotlin 1.7.20+ to use the new memory model for Kotlin/Native and see if this is still an issue.

Update. I have run the iosSimulatorArm64 tests on common-runtime with Kotlin 1.7.21 and they pass fine. So this will be blocked on that, but We can do that separately.

[steve-the-edwards]

• Decide whether removing the strict kotlin.native.memoryModel mode from a test run (as I have done here) is valid after Kotlin 1.7.20.