test-merge-tool: Make sure no hgmerge can be found in $PATH
The merge tool selecting algorithm is hardcoded to look for hgmerge in $PATH
before it falls back to use internal merge. This fixes the test for this
fallback to be tolerant to existing hgmerges.
adding foo
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
adding foo
created new head
rev offset length base linkrev nodeid p1 p2
0 0 0 0 0 b80de5d13875 000000000000 000000000000
1 0 24 0 1 0376abec49b8 000000000000 000000000000