`${}`, `${:}` and so on are invalid because there's
no parameter within the brackets; fix detection for
this situation and add/update tests.
There were some existing test-cases that were testing
for the wrong behavior, which are now updated.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
Upstream-commit: 334bf3ea76004d0abe02dd1698989f9eaf87a86a
Component: engine
1f9af8d4f9