Iterate a Map's entrySet() rather than its keySet()

A loop over map.keySet() that calls map.get(key) hashes and probes the map again for every element, which on a TreeMap costs an extra O(log n) lookup per iteration. Iterating map.entrySet() instead hands the loop both the key and the value. The loop is only rewritten when:

• The map is a simple reference that is neither modified nor reassigned inside the loop.
• get is called only with the loop variable.
• The loop variable is neither reassigned nor captured by a lambda or anonymous class.

Every candidate loop, converted or not, is recorded in a data table along with the reason it was left alone.