
Eliminates an unused ifdef'ed include in embedder_test_backingstore_producer.h and adds it to embedder_test_context_gl.h, where it's needed. The need for this include was eliminated in https://github.com/flutter/engine/pull/56638. No test changes since the patch introduces no semantic changes. Issue: https://github.com/flutter/flutter/issues/158998 [C++, Objective-C, Java style guides]: https://github.com/flutter/engine/blob/main/CONTRIBUTING.md#style