Revert "Create a platform to use in tasks to validate tool chain"

This reverts commit f579b211269e92b9cac3e2c9f515565f9961ccb9.
Revert "Fixes build breakage because we cannot target 1.8 without running at least JDK 8"

This reverts commit 33bfd2a522ff9a57d5f875b5ea02f8072d2b99f3.
Introduced a separate JavaCompile task for new java components