caches: stop warming the cache after 'localrepo.commitctx' Now that we garantee that branchmap cache are updated at the end of the transaction we can drop that one. This removes a problematic case with nested transaction where the new cache could be written on disk before the transaction is finished. The test change is harmless, since we update the cache at a later point, the dirstate have been updated in between.

caches: introduce a 'debugupdatecaches' command That command make sure caches are updated. This is based on 'localrepo.updatecaches' so when we move support for new cache in that function this command will benefit from it.