let apps set statement-cache size.

1. we should let apps set their statement-cache size. right n ow it is 250
is the statement-cache size for all apps and that is wasting
a lot of memory. each prepared statement is averaging about 1k-5K,
depending upon the complexity of sql and schema.
mnake default 25 and let apps increase the size, if they need to.

2. in "adb bugreport" info, print stats on the statement-cache hits/missies
and size (in number of statement cached). this will help us understand
how statement-cache is being used

Change-Id: Ic53a2842ef75823757492778158fcb8d5b4a28bb