Remove code from docs/examples which uses SkBits2Float.

This function is not public API (it lives in include/private) and
does not belong in any user-facing examples.

(For that matter, none of these examples seem useful or relevant.
Why are old bug reproducers saved in the example code?)

Change-Id: I90be446addfc3d5b91977f930723b1a50de96e85
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/842478
Auto-Submit: John Stiles <johnstiles@google.com>
Reviewed-by: Greg Daniel <egdaniel@google.com>
6 files changed