Add OpenJDK 20.0.1

Content of README.google:

Name: Java Development Kit (JDK)
URL: https://jdk.java.net/20/
Version: 20
Revision: NA
License: the GNU General Public License, version 2, with the Classpath Exception.

Description:
This is pulled directly from the website for the JDK releases that has an open source license.
Synlinks have reen resolved using `cp -rL` before uploading.

Bug: b/281902832
Change-Id: I5d4b3171e57ac0d16ba786a7156910947b5ab7be
diff --git a/tools/test.py b/tools/test.py
index 2f0254c..a8e279f 100755
--- a/tools/test.py
+++ b/tools/test.py
@@ -59,6 +59,7 @@
   'jdk9',
   'jdk11',
   'jdk17',
+  'jdk20',
 ] + [ 'dex-%s' % dexvm for dexvm in ALL_ART_VMS ]
 
 def ParseOptions():