Make GrTextBlob initial position const

* Convert from fInitialX, fInitialY to an SkPoint fInitialOrigin
* Start putting params in a consistent order
* inline and remove single use functions

Change-Id: I53eecf6098b475ef05f4f5c4133510ee1104073f
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/257756
Auto-Submit: Herb Derby <herb@google.com>
Commit-Queue: Ben Wagner <bungeman@google.com>
Reviewed-by: Ben Wagner <bungeman@google.com>
4 files changed