Revert of Use unorm shorts for texture coordinates when rendering text. (patchset #3 id:40001 of https://codereview.chromium.org/1713693002/ )

Reason for revert:
Causing issues with text on Mali 400s. Examples: 	largeglyphblur, imageblurtiled. It appears that there are precision problems.

Original issue's description:
> Use unorm shorts for texture coordinates when rendering text.
>
> There are a couple of reasons for this:
> - Vulkan does not guarantee conversions from integral vertex attributes
>   to floating point shader variables
> - This may be faster and more precise on some platforms, as it avoids
>   the aforementioned conversion and changes a multiply by a very small
>   value to a multiply by a medium-sized value.
> GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1713693002
> TBR=bsalomon@google.com
>
> Committed: https://skia.googlesource.com/skia/+/e507ff0460f4f878214b9454fb5b9ab8d64d8063

TBR=joshualitt@google.com
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true

Review URL: https://codereview.chromium.org/1709133003
9 files changed