input: Write a python function to find the 10 most common words in a given text using the `collections.Counter` class.
  assert most_common_words("apple banana apple orange banana apple") == [('apple', 3), ('banana', 2), ('orange', 1)]
  assert most_common_words("cat dog cat bird dog cat bird bird") == [('cat', 3), ('bird', 3), ('dog', 2)]
  assert most_common_words("a a a b b c c c c c d d d e e f f f f f g g g h h h i i i i i i") == [('i', 6), ('c', 5), ('f', 5), ('a', 3), ('d', 3), ('g', 3), ('h', 3), ('b', 2), ('e', 2)]
output: def most_common_words(text):
      from collections import Counter
      words = text.split()
      counter = Counter(words)
      return counter.most_common(10)