feat(ec2): add support for x2iezn instances (#19517)

----

Blogpost: https://aws.amazon.com/blogs/aws/new-amazon-ec2-x2iezn-instances-powered-by-the-fastest-intel-xeon-scalable-cpu-for-memory-intensive-workloads/

Author: cmooreamazon

packages/@aws-cdk/aws-ec2/lib/instance-types.ts

@@ -576,6 +576,16 @@ export enum InstanceClass {
    */
   X2IDN = 'x2idn',
 
+  /**
+   * Memory-intensive instances with higher network bandwith and single-threaded performance, Intel Xeon Scalable (Cascade Lake) processors
+   */
+  MEMORY_INTENSIVE_2_XTZ_INTEL = 'x2iezn',
+
+  /**
+   * Memory-intensive instances with higher network bandwith and single-threaded performance, Intel Xeon Scalable (Cascade Lake) processors
+   */
+  X2IEZN = 'x2iezn',
+
   /**
    * Instances with customizable hardware acceleration, 1st generation
    */