Merge branch 'mk/merge-incomplete-files'

Merging changes into a file that ends in an incomplete line made the
last line into a complete one, even when the other branch did not
change anything around the end of file.

* mk/merge-incomplete-files:
  git-merge-file: do not add LF at EOF while applying unrelated change
  t6023-merge-file.sh: fix and mark as broken invalid tests