Change definitions pertaining to running execution[s] in the spec and javadoc.

[follis]

Several JobOperator methods (like stop, abandon) make reference to 'running executions'. The problem is we never define what batch status values that means and what happens. ---- When exactly is lastUpdatedTime updated?

Just on batch status change at job level (incl. abandon)? Not checkpoints? What about step level events? Also javadoc has typo (repeated 'updated')