revset: fix spanset.isascending() to honor sort() or reverse() request
Because spanset.isascending() ignored the ascending flag, the result of
"fullreposet() & x" was always sorted in ascending order.
The test case is carefully chosen to call fullreposet.__and__.
hg debuginstall
$ hg debuginstall
checking encoding (ascii)...
checking Python executable (*) (glob)
checking Python version (2.*) (glob)
checking Python lib (*lib*)... (glob)
checking installed modules (*mercurial)... (glob)
checking templates (*mercurial?templates)... (glob)
checking commit editor...
checking username...
no problems detected
hg debuginstall with no username
$ HGUSER= hg debuginstall
checking encoding (ascii)...
checking Python executable (*) (glob)
checking Python version (2.*) (glob)
checking Python lib (*lib*)... (glob)
checking installed modules (*mercurial)... (glob)
checking templates (*mercurial?templates)... (glob)
checking commit editor...
checking username...
no username supplied
(specify a username in your configuration file)
1 problems detected, please check your install!
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