Provide Bazel timing breakdown for the mixed builds

Instead of single event in the build metrics
```
| soong_build.mixed_build.bazel          | 1:17.1 |
```
it will now show:
```
| soong_build.mixed_build.bazel          | 1:17.1 |
| soong_build.mixed_build.bazel.cquery   |   51.9 |
| soong_build.mixed_build.bazel.aquery   |   23.1 |
| soong_build.mixed_build.bazel.symlinks |    2.1 |
```

Test: treehugger
Change-Id: I84a7dda6e3122860da9aaa98bfa6afe33d392dcf