--join does not respect types and ratio

When benchmarking multiple types with `--join` option, the resulting table does not group by types, and `Ratio` is completely messed up.

```
| Type | Method | Pending | Mean | Error | StdDev | Ratio | RatioSD | Code Size | Gen 0 | Allocated | Alloc Ratio |
|------------- |------------- |-------- |-----------:|---------:|---------:|------:|--------:|----------:|-------:|----------:|------------:|
| AsyncAwait | Callback | False | 287.8 ns | 2.01 ns | 1.88 ns | 1.00 | 0.00 | 1,561 B | 0.2651 | 832 B | 1.00 |
| ContinueWith | Callback | False | 293.9 ns | 0.70 ns | 0.66 ns | 1.02 | 0.01 | 1,572 B | 0.2651 | 832 B | 1.00 |
| AsyncAwait | ProtoPromise | False | 352.5 ns | 1.53 ns | 1.36 ns | 1.22 | 0.01 | 2,010 B | - | - | 0.00 |
| ContinueWith | ProtoPromise | False | 495.5 ns | 8.59 ns | 8.03 ns | 1.72 | 0.03 | 11,185 B | - | - | 0.00 |
| AsyncAwait | RsgPromise | False | NA | NA | NA | ? | ? | - | - | - | ? |
| ContinueWith | RsgPromise | False | 573.8 ns | 3.57 ns | 2.79 ns | 1.99 | 0.02 | 2,476 B | 0.3290 | 1032 B | 1.24 |
| AsyncAwait | Task | False | 319.3 ns | 1.35 ns | 1.05 ns | 1.11 | 0.01 | 2,496 B | 0.0610 | 192 B | 0.23 |
| ContinueWith | Task | False | 2,231.1 ns | 26.55 ns | 24.84 ns | 7.75 | 0.09 | 9,632 B | 0.3891 | 1224 B | 1.47 |
| AsyncAwait | UniTask | False | 367.2 ns | 1.68 ns | 1.57 ns | 1.28 | 0.01 | 2,425 B | - | - | 0.00 |
| ContinueWith | UniTask | False | 708.9 ns | 8.67 ns | 15.86 ns | 2.51 | 0.07 | 8,385 B | - | - | 0.00 |
| AsyncAwait | ValueTask | False | 485.4 ns | 2.04 ns | 1.59 ns | 1.68 | 0.01 | 2,991 B | - | - | 0.00 |
| ContinueWith | ValueTask | False | NA | NA | NA | ? | ? | - | - | - | ? |
```

Types should be grouped separately with `--join` and `Ratio` respected for each type.

See also #1864 which was regarding categories, but this issue is without categories.