tests: *todo* and *fail* marked as skiped in the XML juint file

There is no way, in the JUnit format to distinguish between *expected
success* and *expected failure*.
But there is a distinction between *run* and *skipped* (shown as green and
yellow by Jenkins).
This hack overload the currently useless *skipped* status to mark expected
failure (todo and fixme).

Signed-off-by: Jean Privat <jean@pryen.org>
tests: cleanup .skip files from old stuff

Signed-off-by: Jean Privat <jean@pryen.org>
tests: add a lot of missing sav/ files

most are empty and from the lib/ directory

Signed-off-by: Jean Privat <jean@pryen.org>
niti: add missing extern&intern methods on Char and Float

Signed-off-by: Jean Privat <jean@pryen.org>
tests: reuse legacy ffi for test_extern.nit

Signed-off-by: Jean Privat <jean@pryen.org>
Merge branch 'tests'