8168712: [AOT] assert(false) failed: DEBUG MESSAGE: InterpreterMacroAssembler::call_VM_base: last_sp != NULL Summary: skip the assert for this specific case, as it is not an issue. Reviewed-by: coleenp, dlong, kvn

8189794: Assert in InstanceKlass::cast called from Exceptions::new_exceptions Summary: Fix call to InstanceKlass::cast to only be after verifying class is non-null. Reviewed-by: dholmes, sspitsyn