resource/aws_emr_cluster: Remove instance_group configuration block…

…, `core_instance_count`, `core_instance_type`, and `master_instance_type` arguments (#14137)

Reference: #13398

Already documented in the version 3 upgrade guide.

Output from acceptance testing:

```
--- PASS: TestAccAWSAppautoscalingScheduledAction_EMR (685.62s)

--- PASS: TestAccAWSAppautoScalingTarget_emrCluster (795.89s)

--- PASS: TestAccAWSEMRCluster_additionalInfo (485.16s)
--- PASS: TestAccAWSEMRCluster_basic (712.73s)
--- PASS: TestAccAWSEMRCluster_bootstrap_ordering (1257.00s)
--- PASS: TestAccAWSEMRCluster_configurationsJson (564.86s)
--- PASS: TestAccAWSEMRCluster_CoreInstanceGroup_AutoscalingPolicy (715.08s)
--- PASS: TestAccAWSEMRCluster_CoreInstanceGroup_BidPrice (1059.01s)
--- PASS: TestAccAWSEMRCluster_CoreInstanceGroup_InstanceCount (626.30s)
--- PASS: TestAccAWSEMRCluster_CoreInstanceGroup_InstanceType (1044.13s)
--- PASS: TestAccAWSEMRCluster_CoreInstanceGroup_Name (1042.89s)
--- PASS: TestAccAWSEMRCluster_custom_ami_id (579.80s)
--- PASS: TestAccAWSEMRCluster_disappears (383.60s)
--- PASS: TestAccAWSEMRCluster_Ec2Attributes_DefaultManagedSecurityGroups (842.05s)
--- PASS: TestAccAWSEMRCluster_keepJob (510.94s)
--- PASS: TestAccAWSEMRCluster_Kerberos_ClusterDedicatedKdc (628.70s)
--- PASS: TestAccAWSEMRCluster_MasterInstanceGroup_BidPrice (881.16s)
--- PASS: TestAccAWSEMRCluster_MasterInstanceGroup_InstanceCount (1119.47s)
--- PASS: TestAccAWSEMRCluster_MasterInstanceGroup_InstanceType (951.90s)
--- PASS: TestAccAWSEMRCluster_MasterInstanceGroup_Name (1090.58s)
--- PASS: TestAccAWSEMRCluster_root_volume_size (807.76s)
--- PASS: TestAccAWSEMRCluster_s3Logging (572.85s)
--- PASS: TestAccAWSEMRCluster_security_config (485.09s)
--- PASS: TestAccAWSEMRCluster_Step_Basic (424.86s)
--- PASS: TestAccAWSEMRCluster_step_concurrency_level (465.70s)
--- PASS: TestAccAWSEMRCluster_Step_ConfigMode (967.37s)
--- PASS: TestAccAWSEMRCluster_Step_Multiple (429.23s)
--- PASS: TestAccAWSEMRCluster_tags (835.98s)
--- PASS: TestAccAWSEMRCluster_terminationProtected (584.57s)
--- PASS: TestAccAWSEMRCluster_visibleToAllUsers (1061.33s)
```

aws/resource_aws_appautoscaling_scheduled_action_test.go

@@ -256,9 +256,14 @@ resource "aws_emr_cluster" "hoge" {
     instance_profile                  = "${aws_iam_instance_profile.instance_profile.arn}"
   }
 
-  master_instance_type = "c4.large"
-  core_instance_type   = "c4.large"
-  core_instance_count  = 2
+  master_instance_group {
+    instance_type = "c4.large"
+  }
+
+  core_instance_group {
+    instance_count = 2
+    instance_type  = "c4.large"
+  }
 
   tags = {
     role     = "rolename"

aws/resource_aws_appautoscaling_target_test.go

@@ -345,9 +345,14 @@ resource "aws_emr_cluster" "tf-test-cluster" {
     instance_profile                  = "${aws_iam_instance_profile.emr_profile.arn}"
   }
 
-  master_instance_type = "m3.xlarge"
-  core_instance_type   = "m3.xlarge"
-  core_instance_count  = 2
+  master_instance_group {
+    instance_type = "m3.xlarge"
+  }
+
+  core_instance_group {
+    instance_count = 2
+    instance_type  = "m3.xlarge"
+  }
 
   tags = {
     role     = "rolename"