deps: add no-strict-aliasing to ICU cflags

This commit adds -Wno-strict-aliasing to the icu_implementation target.
The motivation for this is that this flags is enabled when building with
macosx, and will make the output a little cleaner when building on
other operating systems.

PR-URL: #23112
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: James M Snell <jasnell@gmail.com>

Author: danbev

tools/icu/icu-generic.gyp

@@ -51,7 +51,7 @@
       'direct_dependent_settings': {
         'conditions': [
           [ 'os_posix == 1 and OS != "mac" and OS != "ios"', {
-            'cflags': [ '-Wno-deprecated-declarations' ],
+            'cflags': [ '-Wno-deprecated-declarations', '-Wno-strict-aliasing' ],
             'cflags_cc': [ '-frtti' ],
             'cflags_cc!': [ '-fno-rtti' ],
           }],