[514382] Pre-Merge on conflict can lead to data loss

Ensure that pre-merge merges only diffs from the right side and leaves
the diffs from the left side untouched.

Contains tests.

Bug: 514382
Change-Id: Ie24a595dca3da78d2eda7ea32510d3630b8def9a
Also-by: Simon Delisle <simon.delisle@ericsson.com>
Signed-off-by: Martin Fleck <mfleck@eclipsesource.com>
4 files changed