More updater fixage

Preserve --dir parameter after updating
Allow more than one copy of a command line parameter in MultiMC
Linux runner script no longer changes current directory, which allows '--dir .'
Fixed unit tests, removed the obsolete one (for some legacy updater command line params that were also removed)
[fixes 63127704]

package/linux/MultiMC

@@ -15,7 +15,6 @@ fi
 
 
 MMC_DIR="$(dirname "$(readlink -f "$0")")"
-cd "${MMC_DIR}"
 echo "MultiMC Dir: ${MMC_DIR}"
 
 # Set up env