[SPARK-9854] [SQL] RuleExecutor.timeMap should be thread-safe

`RuleExecutor.timeMap` is currently a non-thread-safe mutable HashMap; this can lead to infinite loops if multiple threads are concurrently modifying the map.  I believe that this is responsible for some hangs that I've observed in HiveQuerySuite.

This patch addresses this by using a Guava `AtomicLongMap`.

Author: Josh Rosen <joshrosen@databricks.com>

Closes #8120 from JoshRosen/rule-executor-time-map-fix.