In 3b12bb225a, ":oldfiles" was taught to
behave like Vim's ":browse oldfiles" if ":oldfiles!" was used. However,
this conflates the use of ! for abandoning a modified buffer with
choosing one file out of a list of oldfiles.
Now that ":browse" is supported again, ":browse oldfiles" will allow the
user to select an old file, while still complaining if that would cause
a modified buffer to be abandoned. ":browse oldfiles!" will just
abandon the buffer, as expected.
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.
- change approach for test 1: screen:expect() instead of assert()
- use execute() instead of command()
- 2 new tests that check none and wrong input for :oldfiles!
Helped-by: @fwalch
Helped-by: @tarruda
Helper-by: @justinmk
