Rename *Cache.newBuilder() methods to defaultBuilder()

newBuilder() made it sound like it was safe to go around calling
arbitrary methods on the builder, whereas in reality the state
checking in CacheBuilder made this risky. The new name should be less
encouraging.

Since we still want to apply the weigher to the BlameCache builder,
extract a separate static method for this.

Change-Id: Ic99d337bbad16a4137a44d00685d97b7baad5d99
3 files changed