Add support for Compare Result command in JUnit view for Groovy assert comparisons

[eric-milles]

When a JUnit test case uses Assert.assertEquals, a test failure displays the option Compare Result in the JUnit view's context menu (see below) for easy comparison of expected and actual strings. If possible, enhance this capability to support Groovy's assert keyword (at least for == comparisons).

[eric-milles]

Note: Spock supports this somehow.