build: Intl: bump ICU4C from 54 to 55 (backport)

node was using ICU4C 54 ( released 2014-oct-06 )

* Bump to ICU4C 55 ( released 2015-apr-08)
 * Timezone fixes, translation fixes, bug/performance fixes.
 * Speed improvements in date formatting
 * ICU4C 55 changelog: http://site.icu-project.org/download/55
 * CLDR 27 changelog: http://cldr.unicode.org/index/downloads/cldr-27

* Retarget the file exclusions from ICU4C 54 to ICU4C 55
 * (improves on-disk footprint on some platforms)

Fixes: #25855

Backport from nodejs/node:
> Originally-Fixes: nodejs/node#2292
> Original-PR-URL: nodejs/node#2293

PR-URL: #25856
Reviewed-By: João Reis <reis@janeasystems.com>
Reviewed-By: James Snell <jasnell@gmail.com>

configure

@@ -748,9 +748,9 @@ def glob_to_var(dir_base, dir_sub):
 def configure_intl(o):
   icus = [
     {
-      'url': 'http://download.icu-project.org/files/icu4c/54.1/icu4c-54_1-src.zip',
-      # from https://ssl.icu-project.org/files/icu4c/54.1/icu4c-src-54_1.md5:
-      'md5': '6b89d60e2f0e140898ae4d7f72323bca',
+      'url': 'http://download.icu-project.org/files/icu4c/55.1/icu4c-55_1-src.zip',
+      # from https://ssl.icu-project.org/files/icu4c/55.1/icu4c-src-55_1.md5:
+      'md5': '4cddf1e1d47622fdd9de2cd7bb5001fd',
     },
   ]
   def icu_download(path):

tools/icu/icu-generic.gyp

@@ -111,8 +111,8 @@
             '<@(icu_src_i18n)'
           ],
           'conditions': [
-            [ 'icu_ver_major == 54', { 'sources!': [
-              ## Strip out the following for ICU 54 only.
+            [ 'icu_ver_major == 55', { 'sources!': [
+              ## Strip out the following for ICU 55 only.
               ## add more conditions in the future?
               ## if your compiler can dead-strip, this will
               ## make ZERO difference to binary size.
@@ -369,8 +369,8 @@
         '<@(icu_src_common)',
       ],
       'conditions': [
-        [ 'icu_ver_major == 54', { 'sources!': [
-          ## Strip out the following for ICU 54 only.
+        [ 'icu_ver_major == 55', { 'sources!': [
+          ## Strip out the following for ICU 55 only.
           ## add more conditions in the future?
           ## if your compiler can dead-strip, this will
           ## make ZERO difference to binary size.