Feature request: Support LLVM lit

It would be nice if the benchmark action could support the [lit](https://llvm.org/docs/CommandGuide/lit.html) the LLVM Integrated Tester.

The json output generated by lit looks as follows:
```
{
"__version__": [
15,
0,
0
],
"elapsed": 13.489635944366455,
"tests": [
{
"code": "PASS",
"elapsed": 13.247512102127075,
"name": "Target :: [Target]/[TestSuite]/[TestName].ll",
"output": "[test output ....] "
}
]
}
```