Add failing test for in-place import with read-only file
Permit passing "mode" to ManagedImportProcess.getUploader

The first time an in-place FileTransfer implementation
acquires the uploader, they "own" the location which will
be eventually contain the fileset. The method checkLocation
will touch that file path in order to check that it is
writeable. After the transfer, however, the FileTransfer
instance may no longer have write access, for example if
the symlinked file belongs to another user. Since opening
a file with "rw" requires write permissions even for the
`size()` operation, it's necessary to downgrade to just "r".
Remove Java8'ism
Merge pull request #3265 from joshmoore/read-only-inplace

Read only inplace