sslutil: require serverhostname argument (API) All callers now specify it. So we can require it. Requiring the argument means SNI will always work if supported by Python. The main reason for this change is to store state on the socket instance to make the validation function generic. This will be evident in subsequent commits.

annotate: optimize line counting We used len(text.splitlines()) to count lines. This allocates, copies, and deallocates an object for every line in a file. Instead, we use count("\n") to count newlines and adjust based on whether there's a trailing newline. This improves the speed of annotating localrepo.py from 4.2 to 4.0 seconds.

purge: use opts.get() Most commands use opts.get() to retrieve values for options that may not be explicitly passed. purge wasn't. This makes it easier to call purge() from 3rd party extensions.

test-run-tests: clean up inuse server eagerly