Revert "MULE-7840: Fixing tests for JDK6."

This reverts commit 7586bb0258d115b41c0a51b9814082129741c351.
Revert "MULE-7840: Fixing assembly whitelist and adding junit version as property on pom."

This reverts commit cccc1663041071c784c983e45460e630011bd442.
Revert "MULE-7840: Upgraded junit to 4.11. Changed mockito-all for core. Adjusted and fixed tests."

This reverts commit 9cdb2fdde7e7287331ae2c76a6814c0892aea425.
Merge pull request #1007 from mulesoft/MULE-7840-REVERT

Mule 7840 revert