[vm] Remove unused dependency on ICU i18n.

TEST=ci
Change-Id: I6a09ef8af516495d479b5969aa89c9b2ceb9dc6f
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/486824
Reviewed-by: Alexander Aprelev <aam@google.com>
Commit-Queue: Ryan Macnak <rmacnak@google.com>

runtime/bin/BUILD.gn

@@ -886,7 +886,6 @@ template("dart_executable") {
       ":crashpad",
       ":icudtl_cc",
       "//third_party/boringssl",
-      "//third_party/icu:icui18n",
       "//third_party/icu:icuuc",
       "//third_party/zlib",
     ]

runtime/vm/BUILD.gn

@@ -73,10 +73,7 @@ library_for_all_configs("libdart_vm") {
   target_type = "source_set"
   extra_product_deps = []
   extra_nonproduct_deps = []
-  extra_deps = [
-    "//third_party/icu:icui18n",
-    "//third_party/icu:icuuc",
-  ]
+  extra_deps = [ "//third_party/icu:icuuc" ]
   if (dart_support_perfetto) {
     extra_deps += [ "//third_party/perfetto:libprotozero" ]
   }
@@ -273,7 +270,6 @@ executable("gen_regexp_special_case") {
   ]
   deps = [
     "../platform:libdart_platform_jit",
-    "//third_party/icu:icui18n",
     "//third_party/icu:icuuc",
   ]
   sources = [ "regexp/gen_regexp_special_case.cc" ]