tests/test-simplemerge.py.out

reachableroots: use internal "revstates" array to test if rev is a root

The main goal of this patch series is to reduce the use of PyXxx() function
that is likely to require ugly error handling and inc/decref. Plus, this is
faster than using PySet_Contains().

  revset #0: 0::tip
  0) 0.004168
  1) 0.003678  88%

This patch ignores out-of-range roots as they are in the pure implementation.
Because reachable sets are calculated from heads, and out-of-range heads raise
IndexError, we can just take out-of-range roots as unreachable. Otherwise,
the test of "hg log -Gr '. + wdir()'" would fail.

"heads" argument is changed to a list. Should we have to rename the C function
as its signature is changed?

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Ran 16 tests in 0.000s

OK