Add detailed error message corresponding to the IndexOutOfBoundsExcep…

…tion while calling getEntry(...) (netty#10386)

Motivation:
`getEntry(...)` may throw an IndexOutOfBoundsException without any error messages.


Modification:

Add detailed error message corresponding to the IndexOutOfBoundsException while calling `getEntry(...)` in HpackDynamicTable.java.

Result: 

Easier to debug

codec-http2/src/main/java/io/netty/handler/codec/http2/HpackDynamicTable.java

@@ -83,7 +83,7 @@ public long capacity() {
      */
     public HpackHeaderField getEntry(int index) {
         if (index <= 0 || index > length()) {
-            throw new IndexOutOfBoundsException();
+            throw new IndexOutOfBoundsException("Index " + index + " out of bounds for length " + length());
         }
         int i = head - index;
         if (i < 0) {