tests/resource/aws_ses_event_destination: Fix Terraform 0.12 syntax
tests/resource/aws_ses_event_destination: Fix Terraform 0.12 syntax

These changes are backwards compatible with Terraform 0.11.

Previous output from Terraform 0.12 acceptance testing:

```
--- FAIL: TestAccAWSSESEventDestination_basic (0.45s)
    testing.go:568: Step 0 error: /opt/teamcity-agent/temp/buildTmp/tf-test591008274/main.tf:82,48-49: Missing newline after argument; An argument definition must end with a newline.
```

Output from Terraform 0.12 acceptance testing:

```
--- PASS: TestAccAWSSESEventDestination_basic (157.86s)
```

kjmkznr/terraform-provider-aws,Ninir/terraform-provider-aws,Ninir/terraform-provider-aws,kjmkznr/terraform-provider-aws,terraform-providers/terraform-provider-aws,terraform-providers/terraform-provider-aws,terraform-providers/terraform-provider-aws,Ninir/terraform-provider-aws,kjmkznr/terraform-provider-aws,kjmkznr/terraform-provider-aws,Ninir/terraform-provider-aws,terraform-providers/terraform-provider-aws