8162546: change hidden options -Xdebug to --debug, -XshouldStop to --should-stop, and -diags to --diags
Reviewed-by: mcimadamore

8161020: javac, fold stop compilation options
Reviewed-by: mcimadamore

8076543: Add @modules as needed to the langtools tests
Reviewed-by: jjg, shurailine

8062348: langtools tests should close file manager (group 1)
Reviewed-by: darcy

8054956: Javac reports wrong error offset for unknown identifier of annotation element/value pair
Summary: When reporting an error about unresolvable annotation attribute, use the position of the explicit left-hand-side of the assignment if available, otherwise use the position of the right-hand-side.
Reviewed-by: jfranck

8017216: javac doesn't fill in end position for some errors of type not found
8019421: Javac doesn't fill in end position for some annotation related errors
8019422: Javac doesn't fill in end position for uninitialized variable errors
Reviewed-by: jjg, mcimadamore