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e400e8c3dc7190b83dec57be9d858ee44e146a42 by Martijn Vels <mvels@google.com>:

Optimize Cord destructor through CordRepBtree::Destroy

This change inlines tree destruction 2 levels at a time, special casing leaf and leaf + 1 levels.

Benchmarks shows this provides up to 8% speed up

PiperOrigin-RevId: 410953099
GitOrigin-RevId: e400e8c3dc7190b83dec57be9d858ee44e146a42
Change-Id: Ic1c123fa0fa2b13cb141ee7a6be155d9e57a0466