This also fixes a failing test (`048 - modifier keys keep context`)
if surrounding text is not supported. If the user presses the
capslock key we shouldn't reset the context if no rules match.
Fixes#5613.
This change adds integration/regression tests for ibus-keyman. It
re-uses the unit tests that we have for core.
Also modifies one test so that the context doesn't use characters
used in the keyboard. This makes it easier to setup in ibus-keyman
tests.
