firebase-ios-sdk

Fix Windows and Fuzzing builds (#5616)

* Add missing dependency on OpenSSL::Crypto

This should fix compilation errors about a missing openssl/err.h when
building against a prebuilt copy of the library.

* Fix Defer usage on Windows

* Fix signedness warnings in CountingQueryEngine

* Rename status_posix.cc to status_errno.cc

Windows excludes *_posix.cc but Status::FromErrno is not conditionally
defined.

This fixes a missing symbol error when building status tests.