Fix feedback loop in ImageTest.SourceRenderbufferTargetTexture* This test would make a renderbuffer as an EGLImage source and a texture as the target. It would then try to verify the data in the texture by sampling but the renderbuffer was currently bound to the framebuffer creating a feedback loop. Bug: angleproject:418022112 Change-Id: I456eb541c84d98d99e6b8d8be817ce67d7b1d519 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/6556610 Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org> Commit-Queue: Geoff Lang <geofflang@chromium.org>