we don't need two ways to disable lowp

SK_DISABLE_LOWP_RASTER_PIPELINE is a little nicer than the old define,
as when enabled we won't even build the lowp stages.

Change-Id: I51d6ca308d8efbb1fc5693d8091a1e6c6d243bf2
Reviewed-on: https://skia-review.googlesource.com/c/164628
Reviewed-by: Mike Klein <mtklein@google.com>
Commit-Queue: Mike Klein <mtklein@google.com>
diff --git a/public.bzl b/public.bzl
index 6452877..d9e927d 100644
--- a/public.bzl
+++ b/public.bzl
@@ -608,7 +608,7 @@
         # Should remove after we update golden images
         "SK_WEBP_ENCODER_USE_DEFAULT_METHOD",
         # Experiment to diagnose image diffs in Google3
-        "SK_JUMPER_DISABLE_8BIT",
+        "SK_DISABLE_LOWP_RASTER_PIPELINE",
         # JPEG is in codec_limited
         "SK_HAS_JPEG_LIBRARY",
     ] + skia_select(