Code now always double quotes the filename to use as command line
argument when calling explorer.exe. In particular, commas in a filename
would be interpreted by explorer.exe as separators for commands.
Similarly a trim_suffix for "file://" is assumed to be a mistake, this
could potentially be a PREfix that we want to strip, but never a suffix.
Since it didn't seem needed in the end, we removed it.
(cherry picked from commit 5608b1d411)
4944a07044