feat(ec2): add support for x2idn and x2iedn instances (#19334)

Blogpost: https://aws.amazon.com/blogs/aws/new-amazon-ec2-x2idn-and-x2iedn-instances-for-memory-intensive-workloads-with-higher-network-bandwidth/

CloudFormation docs are catching up... awsdocs/aws-cloudformation-user-guide#1182

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*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

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

@@ -556,6 +556,26 @@ export enum InstanceClass {
    */
   X2GD = 'x2gd',
 
+  /**
+   * Memory-intensive instances with higher network bandwith, local NVME drive, and extended memory. Intel Xeon Scalable (Ice Lake) processors
+   */
+  MEMORY_INTENSIVE_2_XT_INTEL = 'x2iedn',
+
+  /**
+   *  Memory-intensive instances with higher network bandwith, local NVME drive, and extended memory. Intel Xeon Scalable (Ice Lake) processors
+   */
+  X2IEDN = 'x2iedn',
+
+  /**
+   * Memory-intensive instances with higher network bandwith and local NVME drive, Intel Xeon Scalable (Ice Lake) processors
+   */
+  MEMORY_INTENSIVE_2_INTEL = 'x2idn',
+
+  /**
+   * Memory-intensive instances with higher network bandwith and local NVME drive, Intel Xeon Scalable (Ice Lake) processors
+   */
+  X2IDN = 'x2idn',
+
   /**
    * Instances with customizable hardware acceleration, 1st generation
    */