merge: introduce hasconflicts() on mergeresult object
This and upcoming patches will improve the mergeresult object making it more
powerful and provide clean APIs for various things. Doing this will clean up the
core merge code which is present in `update()` a bit.
Differential Revision: https://phab.mercurial-scm.org/D8816
merge: remove no longer required ACTION_GET_OTHER_AND_STORE
In 1b8fd4af33189c84feadb47c74d659ec31cde3b9 I (ab)used merge actions to pass
info from manifestmerge() to applyupdates() and store info in mergestate.
In previous patches, we introduced a separate return value from manifestmerge()
and calculateupdates() and an argument to applyupdates() which achieved the same
thing.
Let's remove this no longer required messy code.
Differential Revision: https://phab.mercurial-scm.org/D8744