[roll pigweed] pw_sync: Add ConditionVariable facade

ConditionVariable mimics std::condition_variable in terms of API and
semantics. There is one provided backend in pw_sync_stl.

Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/95001

https://pigweed.googlesource.com/pigweed/pigweed
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Change-Id: I9fcee99748034bb86f519c6363e0b9a5967e7833
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/zephyr-integration/+/104710
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1 file changed
tree: e57839140b1fb59cb35ae8d34da081362a411632
  1. .gitmodules
  2. test.sh