Lower the test mismatch warning/error threshold to above iOS 16.9.

Cherry-pick: ef179c2

Author: nglevin

apple/internal/testing/apple_test_bundle_support.bzl

@@ -98,10 +98,10 @@ _DEFAULT_TEST_BUNDLE_ID = "com.bazelbuild.rulesapple.Tests"
 # visible error messaging.
 _TEST_BUNDLE_NAME_SUFFIX = ".__internal__.__test_bundle"
 
-# The lowest minimum OS version that can be used for the test mismatch warning. Higher versions will
-# be "fail"ed instead of issuing a warning to help enforce the minimum OS version to be the same
-# between the test bundle and test host, to avoid debugging issues and redundant build activity.
-_LOWEST_MINIMUM_OS_VERSION_FOR_TEST_MISMATCH_WARNING = "17.4"
+# The highest minimum OS version that can be used for the test mismatch warning. Higher versions
+# will be "fail"ed instead of issuing a warning to help enforce the minimum OS version to be the
+# same between the test bundle and test host to avoid debugging issues and redundant build activity.
+_HIGHEST_MINIMUM_OS_VERSION_FOR_TEST_MISMATCH_WARNING = "16.9"
 
 _ERROR_ON_IOS_TEST_BUNDLE_MISMATCH_PACKAGE_PREFIXES = []
 
@@ -320,7 +320,7 @@ Please assign "{rule_attribute_name}" a value of {test_host_rule_attribute} on t
         # TODO(b/337080510): Apply this failure case to all Apple platforms.
         if platform_prerequisites.platform_type != "ios" or (
             apple_common.dotted_version(test_min_os) > apple_common.dotted_version(
-                _LOWEST_MINIMUM_OS_VERSION_FOR_TEST_MISMATCH_WARNING,
+                _HIGHEST_MINIMUM_OS_VERSION_FOR_TEST_MISMATCH_WARNING,
             ) or any([
                 test_label_package_name.startswith(package_prefix)
                 for package_prefix in _ERROR_ON_IOS_TEST_BUNDLE_MISMATCH_PACKAGE_PREFIXES

test/starlark_tests/common.bzl

@@ -40,7 +40,7 @@ _min_os_ios = struct(
     oldest_supported = "11.0",
     nplus1 = "13.0",
     stable_swift_abi = "12.2",
-    test_mismatch_high_threshold = "18.0",
+    test_mismatch_high_threshold = "17.0",
     widget_configuration_intents_support = "16.0",
 )