The Windows and macOS location providers used to start the MLS provider (with a two-second delay) and then call the operating system's location provider, letting them race. Currently, however, we only start the MLS fallback provider after the system provider returns an error, so the two-second startup delay is just wasted time.
I left the starup delay option in MLSFallback because the Linux gpsd provider still uses it to race MLS with the system's GPS provider.
MozReview-Commit-ID: 3ZFeF1g6PoG
