remove absl experiment

We've given up on Abseil, and these warnings are annoying:

    ... libtool: warning same member name (libabsl.escaping.o) ...

Bug: skia:10165
Change-Id: I144573206174cbe9b48fce8e86ed22eb4a4e29b3
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/329937
Reviewed-by: Mike Klein <mtklein@google.com>
Commit-Queue: Mike Klein <mtklein@google.com>
5 files changed