Make pattern field as static final

Signed-off-by: Pasam Soujanya <psoujany@in.ibm.com>

Author: psoujany

src/jdk.javadoc/share/classes/jdk/javadoc/internal/doclets/formats/html/Table.java

@@ -92,6 +92,8 @@ public class Table<T> extends Content {
     private HtmlStyle gridStyle;
     private final List<Content> bodyRows;
     private HtmlId id;
+    private static String regex = "<(?:a|area|button|input|object|select|textarea)\\b";
+    private static final Pattern pattern = Pattern.compile(regex);
 
     /**
      * A record containing the data for a table tab.
@@ -328,8 +330,6 @@ public void addRow(T item, List<Content> contents) {
             }
         }
         int colIndex = 0;
-        String regex = "<(?:a|area|button|input|object|select|textarea)\\b";
-        Pattern pattern = Pattern.compile(regex);
         for (Content c : contents) {
             HtmlStyle cellStyle = columnStyles.get(colIndex);
             // Always add content to make sure the cell isn't dropped