tests: add more tests for handling of phase divergence by `hg evolve` This patch adds more tests related to handling of phase-divergence by `hg evolve` command.

tests: temporary delete the merge test of handling phase divergence This patch temporary deletes the merge test of handling phase divergence by `hg evolve` command to that other important tests can be plugged in before this. This will make adding more tests easy. As I say, this is temporary to ease out adding more tests, the test will be added back.

tests: various comment on test-evolve-phase-divergence