Cross build alternate_version_generator.exe for Windows ARM64

Bug: 893460
Change-Id: I5618e7da43eb99e59839549c9669deeb61ee65f6
Reviewed-on: https://chromium-review.googlesource.com/c/1474438Reviewed-by: Nico Weber <thakis@chromium.org>
Commit-Queue: Tom Tan <Tom.Tan@microsoft.com>
Cr-Commit-Position: refs/heads/master@{#632662}

chrome/installer/test/BUILD.gn

@@ -2,25 +2,33 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
+import("//build/symlink.gni")
 import("//testing/test.gni")
-
 assert(is_win)
 
-executable("alternate_version_generator") {
-  testonly = true
-  sources = [
-    "alternate_version_generator_main.cc",
-  ]
+if (current_toolchain == host_toolchain) {
+  executable("alternate_version_generator") {
+    testonly = true
+    sources = [
+      "alternate_version_generator_main.cc",
+    ]
 
-  deps = [
-    ":alternate_version_generator_lib",
-    "//base",
-    "//base/test:test_support",
-    "//build/win:default_exe_manifest",
-    "//chrome/common:constants",
-    "//chrome/installer/util:with_rc_strings",
-    "//testing/gtest",
-  ]
+    deps = [
+      ":alternate_version_generator_lib",
+      "//base",
+      "//base/test:test_support",
+      "//build/win:default_exe_manifest",
+      "//chrome/common:constants",
+      "//chrome/installer/util:with_rc_strings",
+      "//testing/gtest",
+    ]
+  }
+} else {
+  binary_symlink("alternate_version_generator") {
+    testonly = true
+    binary_label = ":$target_name($host_toolchain)"
+    binary_output_name = "alternate_version_generator.exe"
+  }
 }
 
 static_library("alternate_version_generator_lib") {