Serialize SIL witness-tables and v-tables and their entries if package cmo is
enabled. If two modules are in the same package and package cmo is enabled,
v-table or witness-table calls should not be generated at the use site in the
client module. Modified conformance serialization check to allow serializing
witness thunks.
Also reordered SIL functions bottom-up so the most nested referenced functions
can be serialized first. Allowed serializing a function if a shared definition
(e.g. function `print`). Added a check for resilient mode wrt struct instructions.
Added tests for SIL tables and resilient mode on/off.
rdar://124632670