8347761: Test tools/jimage/JImageExtractTest.java fails after JDK-8303884

Reviewed-by: dholmes

src/jdk.jlink/share/classes/jdk/tools/jimage/resources/jimage.properties

@@ -93,6 +93,7 @@ main.opt.footer=\
 
 err.not.a.task=task must be one of <extract | info | list | verify>: {0}
 err.missing.arg=no value given for {0}
+err.ambiguous.arg=value for option {0} starts with \"--\" should use {0}=<value> format
 err.not.a.dir=not a directory: {0}
 err.not.a.jimage=not a jimage file: {0}
 err.invalid.jimage=Unable to open {0}: {1}