Added a ClassInfo struct that stores bits for class, strict subclasses and strict subtypes.
This map is initialized empty and lazily computes the bits using the method computeClassInfo.
This function recursively traverses the class hierarchy only when needed, computes the bits on the fly and stores it.
Since the class hierarchy is a DAG, this recursive method terminates.
This map will also be used for some queries, which are now exercised in the new test
Change-Id: I0b8b0b34b5c7d5cc3c1608266c9795033351e650
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/160040
Reviewed-by: Stephen Adams <sra@google.com>
Commit-Queue: Christian Altamirano <coam@google.com>
Christian Altamirano