Integration tests must only go through the real file system/process manager/platform. The global indirection makes this code harder to understand than if it directly referred to the concrete instances that are being used.
Update the integration shard to use a const instance of a LocalFIleSystem, LocalProcessManager, and LocalPlatform. Remove global usage and apply testWithoutContext.
When performing a hot restart, collect isolates without an attached flutter view and send a kill signal. These must have been spawned by running main, so restarting without removing them leads to isolate duplication.
When performing a hot reload, ensure that we send a reloadSources command to every isolate and not just uiIsolates.
