localrepo: improve dirstate.normal lookup by cacheing the function

localrepo: move symlink logic to workingctx

merge: separate worker functions for batch remove and batch get The old code had one function that could do 2 different things. First, is was called a bunch of times to do one thing. Next, it was called a bunch of times to do the other thing. That gave unnecessary complexity and a dispatch overhead. Having separate functions is "obviously" better than having a function that can do two things, depending on its parameters. It also prepares the code for the next refactorings.

merge: change debug logging - test output changes but no real changes Preparing for action list split-up, making sure the final change don't have any test changes. The patch moves debug statements around without really changing anything. Arguably, it temporarily makes the code worse. The only justification is that it makes it easier to review the test changes ... and in the end the big change will not change test output at all. The changes to test output are due to changes in the ordering of debug output. That is mainly because we now do the debug logging for files when we actually process them. Files are also processed in a slightly different but still correct order. It is now primarily ordered by action type, secondarily by filename. The patch introduces some redundancy. Some of it will be removed again, some of it will in the end help code readability and efficiency. It is possible that we later on could introduce a "process this action list and do some logging and progress reporting and apply this function". The "preserving X for resolve" debug statements will only have single space indentation. It will no longer have a leading single space indented "f: msg -> m" message. Having this message double indented would thus no longer make sense. The bid actions will temporarily be sorted using a custom sort key that happens to match the sort order the simplified code will have in the end.