This test runs the WebGL Test listed below in an iframe and reports PASS or FAIL.

Test: ../../resources/webgl_test_files/conformance/context/context-attribute-preserve-drawing-buffer.html
[ 1: PASS ] successfullyParsed is true
[ 2: FAIL ] Did not render ok with preserveDrawingBuffer false.
[ 3: PASS ] Rendered ok with preserveDrawingBuffer true.
[ 4: PASS ] successfullyParsed is true
[ FAIL ] 1 failures reported