#2132 - lint and fix with ale#command#Run

A new function is added here which will later be modified for public use
in linter and fixer callbacks. All linting and fixing now goes through
this new function, to prove that it works in all cases.

test/test_ale_lint_command.vader

@@ -1,7 +1,9 @@
 Before:
   Save g:ale_buffer_info
+  Save g:ale_enabled
 
   let g:ale_buffer_info = {}
+  let g:ale_enabled = 1
 
   let g:expected_loclist = [{
   \ 'bufnr': bufnr('%'),
@@ -58,7 +60,7 @@ Execute(ALELint should run the linters):
   " Try to run the linter a few times, as it fails randomly in NeoVim.
   for b:i in range(5)
     ALELint
-    call ale#engine#WaitForJobs(2000)
+    call ale#test#WaitForJobs(2000)
 
     if !has('nvim')
       " Sleep so the delayed list function can run.