CONSOLE MESSAGE: GPUBuffer.mapReadAsync(): Invalid operation!
CONSOLE MESSAGE: GPUBuffer.mapWriteAsync(): Invalid operation!
CONSOLE MESSAGE: GPUBuffer.mapReadAsync(): Invalid operation!
CONSOLE MESSAGE: GPUBuffer.mapReadAsync(): Invalid operation!

PASS mapReadAsync, unmap, and destroy on a GPUBuffer. 
PASS GPUBuffer.mapReadAsync on a buffer created via GPUDevice.createBufferMapped. 
PASS Reject a map read on a buffer not created with MAP_READ usage. 
PASS Reject a map read on a mapped GPUBuffer. 
PASS Reject a pending map read if GPUBuffer is unmapped.