Plug leak in class initialization.

Don't add static fields and methods to the resolved-items table if the
defining class is still being initialized.  If we do, other threads can
then access those fields and methods without first performing an "is the
class initialized" test.

We will end up performing static field and method resolution more often
now than before.  On a Nexus One, zygote class preload time went from
2227ms to 2239ms (i.e. the performance difference is in the noise).

Bug 2655384.

Change-Id: Ib0c285ef23d58ae709be65f09efb68e73f982084