[TESTBUG] Update expected failure message in runtime/modules/IgnoreModulePropertiesTest.java

The fix for:

JDK-8168836: Minor clean up on warning/error messages on --add-exports and --add-reads

changed the error message when unable to parse and/or locate a named module. The test needs to be updated:

testOption("--patch-module", "=d", "jdk.module.patch.0", "Missing module name");

should now be:

testOption("--patch-module", "=d", "jdk.module.patch.0", "Unable to parse --patch-module");