Roll ICU to 834113

It has two changes:

https://chromium.googlesource.com/chromium/deps/icu.git/+log/42d5027..834113

One is to cherry-pick an integer overflow fix. The other is to fix
ISO-2022-JP encoding.

Now that 373 code points are encoded as expected. Rebaseline the test results
(delete them because all the code points in those files pass).

Bug: 901255, 900059
Test: See bug 900059
Test: LayoutTests: external/wpt/encoding/legacy-mb-japanese/iso-2022-jp
Test: https://www.w3.org/International/tests/repo/run?base=encoding&batch=encoding-dbl-byte&test=legacy-mb-japanese/iso-2022-jp/iso2022jp-encode-form.html
Change-Id: I474ac74c270b77c46f786b28d04494fadb753694
Reviewed-on: https://chromium-review.googlesource.com/c/1317129Reviewed-by: Joshua Bell <jsbell@chromium.org>
Commit-Queue: Jungshik Shin <jshin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#605609}

DEPS

@@ -821,7 +821,7 @@ deps = {
     Var('chromium_git') + '/chromium/deps/hunspell_dictionaries.git' + '@' + 'a9bac57ce6c9d390a52ebaad3259f5fdb871210e',
 
   'src/third_party/icu':
-    Var('chromium_git') + '/chromium/deps/icu.git' + '@' + '42d5027992a0946942839b8821765e1512afbc21',
+    Var('chromium_git') + '/chromium/deps/icu.git' + '@' + '834113aab5c1e5647690f93d9ae25f724095dd40',
 
   'src/third_party/icu4j': {
       'packages': [