(git-submodule) Update EDG submodule url
(Java) Add SgJavaPackageStatement IR Node
(Java) Refactor Java IR Nodes into subdirectory
(Java) Fix Unused Sources policy
(tests) Temporarily remove mergeTest_121.C test

Approved in dquinlan/dq-edg4x-rc (c411d3f6b). I could
not git-cherry-pick Dan's commit because there were a
lot of other modifications in the commit.