Remote Runner: Run multiple workers with one image

It is possible for multiple workers to share a single image by detaching the changes file.

This is required, otherwise multiple OS processes would attempt to write to the same file (GlamorousToolkit.changes) simultaneously, either failing with a write lock, or corrupting the file.

Starting the workers with the flag --detachChangesFromFileSystem will tell GT to write any changes to an internal, memory only, file.

The size of the internal changes and sources files can be determined with:

| sizes |

sizes := Dictionary new.
(PharoFilesOpener classVarNamed: #Default) ifNotNil: [ :filesOpener |
	filesOpener class = PharoLinkFilesOpener ifTrue:
		[ sizes at: #changes put: (filesOpener instVarNamed: #changesVirtual) originalContents size.
		sizes at: #sources put: (filesOpener instVarNamed: #sourcesVirtual) originalContents size. ] ].
sizes.