Convert test_support source sets to static libs

chrome/test/BUILD.gn

Index: chrome/test/BUILD.gn
diff --git a/chrome/test/BUILD.gn b/chrome/test/BUILD.gn
index 1e608bbd442a6c3754c1965ee83f5fc53076a3da..614543e13d1bdb3fd7c6c5281fc1d2ebdcccc32a 100644
--- a/chrome/test/BUILD.gn
+++ b/chrome/test/BUILD.gn
@@ -662,7 +662,7 @@ if (!is_android) {
   }
 
   if (enable_app_list && use_ash) {
-    source_set("test_support_applist_ash") {
+    static_library("test_support_applist_ash") {
       defines = []
       testonly = true
 
@@ -678,7 +678,7 @@ if (!is_android) {
     }
   }
 
-  source_set("sync_integration_test_support") {
+  static_library("sync_integration_test_support") {
     testonly = true
     sources = rebase_path(
             chrome_tests_gypi_values.test_support_sync_integration_sources,
@@ -2431,7 +2431,7 @@ if (!is_android && !is_ios && !is_chromecast) {
   }
 }
 
-source_set("test_support_unit") {
+static_library("test_support_unit") {
   testonly = true
   sources = [
     "../browser/sync/glue/session_sync_test_helper.cc",