test: use generaldelta in 'test-rebase-conflict.t' Doing this has some minor impacts on test output since the rebase backup bundle moves to bundle2.

tests: test generaldelta configuration in test-init.t We turn the feature on for the whole test and test that it can properly be disabled through the config.

test: enable generaldelta early in 'test-treemanifest.t' Having generaldelta on results in minor test output changes (as we are staring at the revlog).