remove dead code behind SK_SUPPORT_LEGACY_SERIALPROCS_REF

Bug: skia:
Change-Id: Iba5ad1e8d5c74c79627cabbbbe4e835278553609
Reviewed-on: https://skia-review.googlesource.com/88820
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Mike Reed <reed@google.com>
2 files changed