glsl-es-3.10: add image/load/atomic predication tests
While working to fix the following test with v3d: dEQP-GLES31.functional.synchronization.inter_call.with_memory_barrier.image_atomic_multiple_interleaved_write_read
we found that predication with image atomic operations were not properly working. This MR includes two tests for that case that had each one a slightly different outcome, plus a normal image load with predication as reference.