Go subtests reported twice

When a subtest fails, gotestsum reports both the test and the subtest:

```
$ gotestsum --format=standard-quiet ./...
FAIL
FAIL example.com/greetings 0.125s

=== Failed
=== FAIL: . TestSayHello/no_input (0.00s)
greetings_test.go:20: want: Hello Person, got: Hello
--- FAIL: TestSayHello/no_input (0.00s)

=== FAIL: . TestSayHello (0.00s)

DONE 4 tests, 2 failures in 0.389s
```

The same test failure run with plain `go test` also shows the nesting but it is only reported once:
```
$ go test ./...
--- FAIL: TestSayHello (0.00s)
--- FAIL: TestSayHello/no_input (0.00s)
greetings_test.go:20: want: Hello Person, got: Hello
FAIL
FAIL example.com/greetings 0.116s
FAIL
```

Is there a way around that? This shows up as two separate test failures in CircleCI which impacts our ability to accurately report on test failures without having to manually dedupe the data. The output in the CircleCI UI looks like this:

Here's the JSON output from `go test --json` which seems to match the gotestsum JSON output as well:

```
{"Time":"2021-06-30T16:03:22.288363Z","Action":"run","Package":"example.com/greetings","Test":"TestSayHello"}
{"Time":"2021-06-30T16:03:22.288528Z","Action":"output","Package":"example.com/greetings","Test":"TestSayHello","Output":"=== RUN TestSayHello\n"}
{"Time":"2021-06-30T16:03:22.288537Z","Action":"run","Package":"example.com/greetings","Test":"TestSayHello/no_input"}
{"Time":"2021-06-30T16:03:22.288543Z","Action":"output","Package":"example.com/greetings","Test":"TestSayHello/no_input","Output":"=== RUN TestSayHello/no_input\n"}
{"Time":"2021-06-30T16:03:22.28858Z","Action":"output","Package":"example.com/greetings","Test":"TestSayHello/no_input","Output":" greetings_test.go:20: want: Hello Person, got: Hello \n"}
{"Time":"2021-06-30T16:03:22.288589Z","Action":"run","Package":"example.com/greetings","Test":"TestSayHello/first_name"}
{"Time":"2021-06-30T16:03:22.288593Z","Action":"output","Package":"example.com/greetings","Test":"TestSayHello/first_name","Output":"=== RUN TestSayHello/first_name\n"}
{"Time":"2021-06-30T16:03:22.288597Z","Action":"run","Package":"example.com/greetings","Test":"TestSayHello/full_name"}
{"Time":"2021-06-30T16:03:22.2886Z","Action":"output","Package":"example.com/greetings","Test":"TestSayHello/full_name","Output":"=== RUN TestSayHello/full_name\n"}
{"Time":"2021-06-30T16:03:22.288608Z","Action":"output","Package":"example.com/greetings","Test":"TestSayHello","Output":"--- FAIL: TestSayHello (0.00s)\n"}
{"Time":"2021-06-30T16:03:22.288612Z","Action":"output","Package":"example.com/greetings","Test":"TestSayHello/no_input","Output":" --- FAIL: TestSayHello/no_input (0.00s)\n"}
{"Time":"2021-06-30T16:03:22.288616Z","Action":"fail","Package":"example.com/greetings","Test":"TestSayHello/no_input","Elapsed":0}
{"Time":"2021-06-30T16:03:22.288625Z","Action":"output","Package":"example.com/greetings","Test":"TestSayHello/first_name","Output":" --- PASS: TestSayHello/first_name (0.00s)\n"}
{"Time":"2021-06-30T16:03:22.288727Z","Action":"pass","Package":"example.com/greetings","Test":"TestSayHello/first_name","Elapsed":0}
{"Time":"2021-06-30T16:03:22.288736Z","Action":"output","Package":"example.com/greetings","Test":"TestSayHello/full_name","Output":" --- PASS: TestSayHello/full_name (0.00s)\n"}
{"Time":"2021-06-30T16:03:22.28874Z","Action":"pass","Package":"example.com/greetings","Test":"TestSayHello/full_name","Elapsed":0}
{"Time":"2021-06-30T16:03:22.288743Z","Action":"fail","Package":"example.com/greetings","Test":"TestSayHello","Elapsed":0}
{"Time":"2021-06-30T16:03:22.288746Z","Action":"output","Package":"example.com/greetings","Output":"FAIL\n"}
{"Time":"2021-06-30T16:03:22.288888Z","Action":"output","Package":"example.com/greetings","Output":"FAIL\texample.com/greetings\t0.102s\n"}
{"Time":"2021-06-30T16:03:22.288903Z","Action":"fail","Package":"example.com/greetings","Elapsed":0.102}
```

Here is the example function:

```go
package greetings

func SayHello(s string) string {
return "Hello " + s
}

```

And its test:

```go
package greetings

import "testing"

func TestSayHello(t *testing.T) {
tests := []struct {
name string
input string
output string
}{
{"no input", "", "Hello Person"},
{"first name", "First", "Hello First"},
{"full name", "First Last", "Hello First Last"},
}

for _, test := range tests {
t.Run(test.name, func(t *testing.T) {
got := SayHello(test.input)
if test.output != got {
t.Fatalf("want: %s, got: %s", test.output, got)
}
})
}
}

```

The `go.mod` file is simply:

```
module example.com/greetings

go 1.15

```

Reproduce the duplicate reporting with the provided greetings_test.go example, then trace how gotestsum consumes the go test --json event stream and formats its JSON output. Compare parent and subtest fail events; done means a single failed test is reported for the nested failure while the existing output remains accurate.

Written by the indexing model from the issue text.