Escaping from a '-- More --' prompt in tests is awkward as it doesn't
take keys from the typebuffer, requiring a call to `feed()` in lua at
the correct time. Moreover, it's rarer that a test will want the
'-- More --' prompt to be activated than not.
It is otherwise impossible to determine which test failed sanitizer/valgrind
check. test/functional/helpers.lua module return was changed so that tests which
do not provide after_each function to get new check will automatically fail.
- The syntax `gui=` is invalid when setting properties of highlight group.
- Wait for the initial "-- More --" prompt before continuing. Required to avoid
a race condition