Builtin precision tests

On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE".


Start testcase: precision.round.lowp_vertex.scalar
FAIL precision.round.lowp_vertex.scalar: 14212/16404 inputs failed.

Start testcase: precision.round.lowp_vertex.vec2
FAIL precision.round.lowp_vertex.vec2: 16158/16404 inputs failed.

Start testcase: precision.round.lowp_vertex.vec3
FAIL precision.round.lowp_vertex.vec3: 16362/16404 inputs failed.

Start testcase: precision.round.lowp_vertex.vec4
FAIL precision.round.lowp_vertex.vec4: 16394/16404 inputs failed.

Start testcase: precision.round.lowp_fragment.scalar
FAIL precision.round.lowp_fragment.scalar: 14212/16404 inputs failed.