Chrome 62's default is to turn off Flash for websites.
Sauce Labs attempted to change this default Chrome setting on its virtual machines, however, there seems to be no programatic way to enable Flash across all OS images that support Chrome 62. For this reason, Flash is not enabled on Chrome 62 on any OS.
If you are running tests that require Flash, you will likely see a pop-up requesting you allow Flash. If this causes an issue during your test, you will need to add an additional step in your script to select 'Allow' when the pop-up appears. This article from StackOverflow includes a number of examples of how to accomplish this.