Problem: Various inconsistencies in test files.
Solution: Add modelines where they were missing. Use Check commands instead
of silently skipping over tests. Adjust indents and comments.
(Ken Takata, closes#6695)
Problem: Tests using term_wait() can still be flaky.
Solution: Increase the wait time when rerunning a test. (James McCoy,
closes#5899) Halve the initial times to make tests run faster
when there is no rerun.
Problem: Cursor position wrong when characters are concealed and asearch
causes a scroll.
Solution: Fix the cursor column in a concealed line after window scroll.
(closes#5215, closes#5012)
Problem: Some balloon tests don't run when they can.
Solution: Split GUI balloon tests off into a separate file. (Ozaki Kiichi,
closes#4538) Change the feature check into a command for
consistency.
Problem: When a match ends in part of concealed text highlighting, it might
mess up concealing by resetting prev_syntax_id.
Solution: Do not reset prev_syntax_id and add a test to verify. (Christian
Brabandt, closes#1092)
Problem: syn-cchar defined with matchadd() does not appear if there are no
other syntax definitions which matches buffer text.
Solution: Check for startcol. (Ozaki Kiichi, haya14busa, closes#757)
