Send --release flag to iOS test runner when is_debug=false

Forward a --release flag to indicate a release run for iOS test
runners when is_debug=false.

Bug: 1056887
Change-Id: Ic9941745084376b85938b1b98e1afb01cc254384
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2105070
Commit-Queue: Jeff Yoon <jeffyoon@chromium.org>
Reviewed-by: John Budorick <jbudorick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#753128}

build/config/ios/ios_test_runner_wrapper.gni

@@ -94,10 +94,6 @@ template("ios_test_runner_wrapper") {
       "${shards}",
     ]
 
-    if (use_clang_coverage) {
-      executable_args += [ "--use-clang-coverage" ]
-    }
-
     # test runner relies on iossim if use_ios_simulator (defined in ios_sdk.gni)
     if (use_ios_simulator) {
       _rebased_root_build_dir = rebase_path("${root_build_dir}", root_build_dir)
@@ -112,6 +108,14 @@ template("ios_test_runner_wrapper") {
       ]
     }
 
+    if (use_clang_coverage) {
+      executable_args += [ "--use-clang-coverage" ]
+    }
+
+    if (!is_debug) {
+      executable_args += [ "--release" ]
+    }
+
     # wrapper script output name and path
     if (!defined(wrapper_output_name)) {
       _wrapper_output_name = "run_${target_name}"