FOP-2530: fix performance regression in MultiByteFont.findGlyphIndex as suggested by dvineshkumar@gmail.com

git-svn-id: https://svn.apache.org/repos/asf/xmlgraphics/fop/trunk@1705133 13f79535-47bb-0310-9956-ffa450edef68

src/java/org/apache/fop/fonts/MultiByteFont.java

@@ -237,6 +237,9 @@ public class MultiByteFont extends CIDFont implements Substitutable, Positionabl
                 if (idx < NUM_MOST_LIKELY_GLYPHS) {
                     mostLikelyGlyphs[idx] = retIdx;
                 }
+                if (retIdx != 0) {
+                    break;
+                }
             }
         }
         return retIdx;