Revert of Try using std::call_once (patchset #1 id:1 of https://codereview.chromium.org/1550893002/ )

Reason for revert:
Can't use on XP.  :(

Original issue's description:
> Try using std::call_once
>
> Now that we've got std library support, perhaps we should start using it.
> This CL acts as a little canary, and may help fix the linked bug.
>
> I'm not really sure what's going on in the linked bug, but using
> std::call_once over homegrown atomics has to be the right answer...
>
> BUG=chromium:418041
> GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1550893002
> CQ_EXTRA_TRYBOTS=client.skia:Test-Ubuntu-GCC-GCE-CPU-AVX2-x86_64-Release-SKNX_NO_SIMD-Trybot
>
> Going to land this ahead of review while the tree is quiet to see how it rolls.
> TBR=herb@google.com
>
> Committed: https://skia.googlesource.com/skia/+/8895b72f789e5dc8bb99cb9727875439005fc919

TBR=herb@google.com,mtklein@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=chromium:418041

Review URL: https://codereview.chromium.org/1552333003