Massively reduce the amount of code needed for linter tests

autoload/ale/fixers/tslint.vim

@@ -2,7 +2,7 @@
 " Description: Fixing files with tslint.
 
 function! ale#fixers#tslint#Fix(buffer) abort
-    let l:executable = ale_linters#typescript#tslint#GetExecutable(a:buffer)
+    let l:executable = ale#handlers#tslint#GetExecutable(a:buffer)
 
     let l:tslint_config_path = ale#path#ResolveLocalPath(
     \   a:buffer,