Operation cloned Input/Output shapes can collide with types shape of same name

[jasdel]

The (de)serializer codegen looks like it can collide cloned operation input/output shapes with types of the same name used nested within the shape tree.

./test_submodules.sh service/glacier 'go test -run NONE'
Testing github.com/aws/aws-sdk-go-v2/service/glacier
# github.com/aws/aws-sdk-go-v2/service/glacier [github.com/aws/aws-sdk-go-v2/service/glacier.test]
./deserializers.go:1443:60: cannot use &output (type **DescribeVaultOutput) as type **types.DescribeVaultOutput in argument to awsRestjson1_deserializeDocumentDescribeVaultOutput
./deserializers.go:5354:6: awsRestjson1_deserializeDocumentDescribeVaultOutput redeclared in this block
	previous declaration at ./deserializers.go:1519:106
FAIL	github.com/aws/aws-sdk-go-v2/service/glacier [build failed]