Remove an unused early-out test from the critical path for
dict and set lookups.
When the strings already have matching lengths, kinds, and hashes,
there is no additional information gained by checking the first
characters (the probability of a mismatch is already known to
be less than 1 in 2**64).
I moved the unicode_eq to stringlib/eq.h to keep the function static and possible inline for setobject.c and dictobject.h. I also removed the unused _PyString_Eq method. If it's required in the future it can be added to eq.h
Raymond Hettinger
Antoine Pitrou
Martin v. Löwis
Christian Heimes