RLS cleanups

[ejona86]

From #11203 :

Seems like the LinkedHashLruCacheTest tests should use cache.fitToLimit() at least some of the time (or maybe it deserves its own test case).

grpc-java/rls/src/main/java/io/grpc/rls/LinkedHashLruCache.java

Line 72 in e4e7f3a

this.evictionListener = new SizeHandlingEvictionListener(evictionListener);

Having the evictionListener handle decrementing estimatedMaxSizeBytes seems like unnecessary complexity that should be eliminated.

grpc-java/rls/src/main/java/io/grpc/rls/LinkedHashLruCache.java

Line 248 in e4e7f3a

// new size is larger no need to do cleanup

The reason given in the comment only describes what happens when it is called from this class, not from RlsAsyncLruCache. The comment should probably just be removed as obvious, but could be changed to there is space available so no need to do cleanup

s/until new size limit/until the size of all entries fits within the limit/