Use separate SKSHAPER_DLL define to activate shared library logic

Change-Id: I35cd463fd85920651a940a9af131f7b6515c2a3a
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/267676
Reviewed-by: Mike Klein <mtklein@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
2 files changed