I tried a fresh instal and todays version blender-2.80.0-git.480a09a92f7f-windows64 simply does not have the -Remove Doubles_ command
I don’t have the most recent but:
Tried Right Click while in edit mode?
Tried searching the Mesh menu?
I’m thinking it’s something the )(*@&#^#%$ at Microsoft did since I used it this morning when making my board surround but it was gone when I went to make the queen.
I rolled back blender to the May 1 version and it was back though…