mesa: In conditional rendering fallback, check the query status.

Otherwise, conditional rendering always takes the fallthrough "render it
anyway" case unless the application had itself done a check or wait on the
query.

Fixes intel oglconform's conditional_render advanced.nofbo.readpixels.

Reviewed-by: Brian Paul <brianp@vmware.com>
NOTE: This is a candidate for the 8.0 branch.

src/mesa/main/condrender.c

@@ -139,6 +139,8 @@ _mesa_check_conditional_render(struct gl_context *ctx)
    case GL_QUERY_BY_REGION_NO_WAIT:
       /* fall-through */
    case GL_QUERY_NO_WAIT:
+      if (!q->Ready)
+         ctx->Driver.CheckQuery(ctx, q);
       return q->Ready ? (q->Result > 0) : GL_TRUE;
    default:
       _mesa_problem(ctx, "Bad cond render mode %s in "