use Make instead of Create to return a shared shader

Partially updated call sites. Undefine the flag in SkSHader.h to convert the remaining sites.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1772463002

Review URL: https://codereview.chromium.org/1772463002
68 files changed