tests: make hghave handle exec bit on Linux with vfat

tests: teach hghave to actually test for symlink support

merge with stable

merge with i18n

graphlog: handle old-style --rev values --rev options cannot be merged into a single revset because we do not know if they are valid revset or old-style revision specifications, like 'foo-bar' tags. Instead, a base revision set is generated with scmutil.revrange() then filtered with the revset built from log options. It also fixes incorrect or hostile expressions passed in --rev.

test-glog: pretty print revset expressions