Fix test case tests/unit-tests/regexp-exec.js

Execution of this test case:
* First call:
  |foo bar baz
  foo| bar baz
  foo bar |baz
  -> "baz" is pushed to the end of the list, l is ["baz"]
* Second call:
  foo bar baz|
  |foo bar baz
  foo |bar baz
  -> "bar" is pushed to the end of the list, l is ["baz", "bar"]
etc.
Merge pull request #31 from ProgVal/fix-test-regexp-exec

Fix test case tests/unit-tests/regexp-exec.js