Update minimum_os_version for XCTest support in Xcode 15.3. Add additional references to common.bzl test targets where it's convenient.

[luispadron]

This leaves the "examples" targets alone, as we're assuming that they should be documentation.

Cherry-pick: https://github.com/bazelbuild/rules_apple/commit/ce6f443590f424fed6839a88bbf6feec301c8904