Before:
  runtime ale_linters/dart/dartanalyzer.vim

After:
  call ale#linter#Reset()

Execute(Basic problems should be parsed correctly):
  AssertEqual
  \ [
  \   {
  \     'type': 'E',
  \     'text': 'expected_token: Expected to find ''}''',
  \     'lnum': 5,
  \     'col': 1,
  \   },
  \   {
  \     'type': 'W',
  \     'text': 'invalid_assignment: A value of type ''String'' can''t be assigned to a variable of type ''int''',
  \     'lnum': 2,
  \     'col': 16,
  \   },
  \ ],
  \ ale_linters#dart#dartanalyzer#Handle(bufnr(''), [
  \ 'Analyzing main.dart...',
  \ '  error • Expected to find ''}'' at main.dart:5:1 • expected_token',
  \ '  warning • A value of type ''String'' can''t be assigned to a variable of type ''int'' at main.dart:2:16 • invalid_assignment',
  \ '1 error and 1 warning found.',
  \ ])