Added EC2ThrottledException as a throttling exception

Author: spfink

.changes/next-release/feature-AmazonEC2-653c75c.json

@@ -0,0 +1,5 @@
+{
+    "category": "Amazon EC2", 
+    "type": "feature", 
+    "description": "Adds EC2ThrottledException as a recognized throttling exception to be retried"
+}

core/aws-core/src/main/java/software/amazon/awssdk/awscore/internal/AwsErrorCode.java

@@ -45,6 +45,7 @@ public final class AwsErrorCode {
         throttlingErrorCodes.add("RequestThrottled");
         throttlingErrorCodes.add("RequestThrottledException");
         throttlingErrorCodes.add("LimitExceededException");
+        throttlingErrorCodes.add("EC2ThrottledException");
         THROTTLING_ERROR_CODES = unmodifiableSet(throttlingErrorCodes);
 
         Set<String> definiteClockSkewErrorCodes = new HashSet<>(3);

core/aws-core/src/test/java/software/amazon/awssdk/awscore/retry/AwsRetryPolicyTest.java

@@ -102,6 +102,17 @@ public void doesNotRetryOnNonRetryableErrorCode() {
         assertFalse(shouldRetry(applyErrorCode("ValidationError")));
     }
 
+    @Test
+    public void retriesOnEC2ThrottledException() {
+        AwsServiceException ex = AwsServiceException.builder()
+                                                    .awsErrorDetails(AwsErrorDetails.builder()
+                                                                                    .errorCode("EC2ThrottledException")
+                                                                                    .build())
+                                                    .build();
+
+        assertTrue(shouldRetry(b -> b.exception(ex)));
+    }
+
     private boolean shouldRetry(Consumer<RetryPolicyContext.Builder> builder) {
         return defaultRetryCondition().shouldRetry(RetryPolicyContext.builder().applyMutation(builder).build());
     }