Android SDK: remove `backtrace()` workaround in swift-testing

[grynspan]

https://github.com/swift-android-sdk/swift-android-sdk/blob/4bbceb9901182cd25a1155cea8bcad6f2e0b7311/apply-patches.sh#L36

The Swift Testing repo has been updated to resolve this issue, so the patch/workaround can be removed now.

[finagolfin]

That patch script is entirely unused, this substitution is what the official CI uses to work around this issue, so the change you just made is entirely disabled for Android on the official CI. Once #available is working for Android in trunk, I will use that instead and then exclude that substitution.