feat(ec2): support for r7i instance type in aws-ec2 (#27737)

Support of R7i EC2-Instance type in aws-ec2.

The [R7i](https://aws.amazon.com/ec2/instance-types/r7i/) was recently introduced in October 2023.
The R7i instance type has been confirmed to be supported in [AWS-Cloudformation](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-ec2-instance.html#cfn-ec2-instance-instancetype).

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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*

Author: kevntao

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

@@ -347,12 +347,22 @@ export enum InstanceClass {
   R7GD = 'r7gd',
 
   /**
-   * Memory optimized instances based on Intel Xeon Scalable (Sapphire Rapids) processors, 7th generation
+   * Memory optimized instances based on Intel Xeon Scalable (Sapphire Rapids) processors, 7th generation w/  3.2GHz turbo frequency
+   */
+  MEMORY7_INTEL_BASE = 'memory7-intel-base',
+
+  /**
+   * Memory optimized instances based on Intel Xeon Scalable (Sapphire Rapids) processors, 7th generation w/  3.2GHz turbo frequency
+   */
+  R7I = 'r7i',
+
+  /**
+   * Memory optimized instances based on Intel Xeon Scalable (Sapphire Rapids) processors, 7th generation, with sustained 3.9GHz turbo frequency
    */
   MEMORY7_INTEL = 'memory7-intel',
 
   /**
-   * Memory optimized instances based on Intel Xeon Scalable (Sapphire Rapids) processors, 7th generation
+   * Memory optimized instances based on Intel Xeon Scalable (Sapphire Rapids) processors, 7th generation, with sustained 3.9GHz turbo frequency
    */
   R7IZ = 'r7iz',
 
@@ -1335,6 +1345,8 @@ export class InstanceType {
       [InstanceClass.R7G]: 'r7g',
       [InstanceClass.MEMORY7_GRAVITON3_NVME_DRIVE]: 'r7gd',
       [InstanceClass.R7GD]: 'r7gd',
+      [InstanceClass.MEMORY7_INTEL_BASE]: 'r7i',
+      [InstanceClass.R7I]: 'r7i',
       [InstanceClass.MEMORY7_INTEL]: 'r7iz',
       [InstanceClass.R7IZ]: 'r7iz',
       [InstanceClass.MEMORY7_AMD]: 'r7a',