largefiles: backout f72d73937853 - linear updates handle m -> a differently f72d73937853 introduced a significant performance regression: All largefiles were marked 'normallookup' by linear (or noop) updates and had to be rehashed by the next command. The previous change introduced a different solution to the problem f72d73937853 solved and we can thus back it out again.

@echo off
rem launch hg.exe from parent folder
"%~dp0\..\hg.exe" %*