8216559: [JFR] Native libraries not correctly parsed from /proc/self/maps

Summary: Use %7s for the dev scan format as major:minor may be up to that length
Reviewed-by: mgronlun, jwilhelm

test/jdk/jfr/event/runtime/TestNativeLibrariesEvent.java

@@ -39,6 +39,7 @@ import jdk.test.lib.jfr.Events;
 
 /**
  * @test
+ * @bug 8216559
  * @key jfr
  *
  * @library /lib /