Revert "Roll ICU 79326efe..83b2ac66"

This reverts commit 22a5368c.

Reason for revert: This roll breaks ChromeOS build as discussed in crbug.com/1129473. The fix https://chromium.googlesource.com/chromium/deps/icu.git/+/aef20f06d47ba76fdf13abcdb033e2a408b5a94d should be included (see crrev.com/c/2425287)

Original change's description:
> Roll ICU 79326efe..83b2ac66
> 
> https://chromium.googlesource.com/chromium/deps/icu.git/+log/79326efe..83b2ac66
> 83b2ac66 [fuchsia] Bring more changes from the Fuchsia copy
> 368b1cb1 Upstream Fuchsia changes in build file
> fb520a53 Add CPEPrefix.
> 
> Bug: 1124037, fuchsia:56362
> Change-Id: Ia77c08b48668de4315b44d3b72a3a3e23d722494
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2412548
> Auto-Submit: Fabrice de Gans-Riberi <fdegans@chromium.org>
> Commit-Queue: Frank Tang <ftang@chromium.org>
> Reviewed-by: Frank Tang <ftang@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#809634}

TBR=fdegans@chromium.org,jshin@chromium.org,ftang@chromium.org

Change-Id: I49d0e15b5089f840e2cd27ba024a22dfeb4bce8a
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 1124037
Bug: fuchsia:56362
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2425390Reviewed-by: Jun Mukai <mukai@chromium.org>
Commit-Queue: Jun Mukai <mukai@chromium.org>
Cr-Commit-Position: refs/heads/master@{#809694}

DEPS

@@ -1032,7 +1032,7 @@ deps = {
     Var('chromium_git') + '/chromium/deps/hunspell_dictionaries.git' + '@' + '18e09b9197a3b1d771c077c530d1a4ebad04c167',
 
   'src/third_party/icu':
-    Var('chromium_git') + '/chromium/deps/icu.git' + '@' + '83b2ac66d1572c2357e1184d2c54d91e7e92c524',
+    Var('chromium_git') + '/chromium/deps/icu.git' + '@' + '79326efe26e5440f530963704c3c0ff965b3a4ac',
 
   'src/third_party/icu4j': {
       'packages': [