This allows you to specify the exit scope amongst existing logging scopes, both in API and the CLI.
e.g for the CLI.
```bash
$ wazero run --hostlogging=exit,filesystem --mount=.:/:ro cat.wasm
```
e.g. for Go
```go
loggingCtx := context.WithValue(testCtx, experimental.FunctionListenerFactoryKey{},
logging.NewHostLoggingListenerFactory(&log, logging.LogScopeExit|logging.LogScopeFilesystem))
```
This is helpful to know if the wasm called exit or if it exited
implicitly. This is one of the few host functions that exists in three
places: assemblyscript, gojs and wasi.
Signed-off-by: Adrian Cole <adrian@tetrate.io>