GitLab

Following r833080 this change removes the explicit noexcept specifier
from flat_tree's move operations, since the compiler will perform the
expected outcome anyway [1]. Furthermore, this change adds tests to
statically assert the correct behavior.

[1] https://timsong-cpp.github.io/cppwp/n4140/dcl.fct.def.default#2.2

Bug: None
Change-Id: I88cd95bf577899925dd8b07a2865b6d2c6f318ed
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2567929Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Commit-Queue: Jan Wilken Dörrie <jdoerrie@chromium.org>
Cr-Commit-Position: refs/heads/master@{#833456}