We are still trying to reproduce the issue as described so we can figure out how to correct the software rasterizer fallback and/or warn the user that the AVD is not correctly configured for optimum performance. I, on the other hand, on a Mac workstation could not even launch the emulator at that configuration (QEMU crashes). This was even though the "Emulator Performance" option was disabled for him too exactly like described in the comment above. on his Linux workstation was able to get create the AVD with host GPU passthrough working just fine. The Android emulator configuration we are trying to get working here is: Nexus 5x with Google Play Store Image on API 25.
The emulators seems to be sensitive to the Android API version as well as the host platform.
Flutter (on Mac OS X 10.12.5 16F73, locale en-US, channel master)