remove guard for new memory porting layer

Bug: skia:
Change-Id: I14f1b421bc4055ea5a7c22735b2605eb883e4f81
Reviewed-on: https://skia-review.googlesource.com/91462
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Mike Reed <reed@google.com>
diff --git a/public.bzl b/public.bzl
index d856db2..1e28940 100644
--- a/public.bzl
+++ b/public.bzl
@@ -586,7 +586,6 @@
       "SK_JUMPER_DISABLE_8BIT",
       # JPEG is in codec_limited
       "SK_HAS_JPEG_LIBRARY",
-      "SK_SUPPORT_LEGACY_MALLOC_PORTING_LAYER",
   ] + skia_select(
       os_conditions,
       [