8316879: RegionMatches1Tests fails if CompactStrings are disabled after JDK-8302163

Reviewed-by: simonis, rgiulietti, rriggs

src/java.base/share/classes/java/lang/String.java

@@ -2156,6 +2156,10 @@ public final class String
              (ooffset > (long)other.length() - len)) {
             return false;
         }
+        // Any strings match if len <= 0
+        if (len <= 0) {
+           return true;
+        }
         byte[] tv = value;
         byte[] ov = other.value;
         byte coder = coder();