Prevent `Mr Bean` from materializing types under `java.*` package

[cowtowncoder]

(note: offshoot of FasterXML/jackson-modules-java8#215)

Looks like Mr Bean's AbstractTypeMaterializer method _suitableType() has a list of about dozen classes NOT to generate implementation for -- all under java.lang, java.util or java.io.
But it seems better to simply block everything under java.*, at this point; if further configurability needed we can add pluggable handler or something. For now, users can sub-class AbstractTypeMaterializer.

[cowtowncoder]

Ok, so:

• 2.12(.4): prevents java.util.TimeZone materialization (the original case) but makes no other changes
• 2.13(.0): by default blocks all java.* types (we'll see if there are counter examples we should materialize)