Roll ICU to 2b12f87 from 8d342a4
Roll ICU to 2b12f87 from 8d342a4

Cherry-pick an upstream patch. See
https://chromium.googlesource.com/chromium/deps/icu/+/2b12f8775d66568f2b2e2bd8246efcfdff40d563 for the change.

BUG=575206
TEST=see comment 51 in the bug
TBR=mmoroz

Review URL: https://codereview.chromium.org/1654883005

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#372868}

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