#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_format_temporary_file_creation.vader

@@ -13,6 +13,7 @@ Before:
   let g:ale_echo_cursor = 0
   let g:ale_enabled = 1
   let g:ale_run_synchronously = 1
+  unlet! g:ale_run_synchronously_callbacks
   let g:ale_set_highlights = 0
   let g:ale_set_loclist = 0
   let g:ale_set_quickfix = 0
@@ -41,6 +42,7 @@ Before:
 After:
   Restore
 
+  unlet! g:ale_run_synchronously_callbacks
   unlet! g:output
   delfunction TestCallback
 
@@ -56,5 +58,6 @@ Execute(ALE should be able to read the %t file):
   AssertEqual 'foobar', &filetype
 
   ALELint
+  call ale#test#FlushJobs()
 
   AssertEqual ['foo', 'bar', 'baz'], g:output