Incorrect `fuzzer_name`s in some projects

some `fuzzer_name` values are reported as the fuzzer path. e.g. https://introspector.oss-fuzz.com/api/project-summary?project=tinyusb has:

```
"fuzzer_name":"/src/tinyusb/test/fuzz/device/msc/src/fuzz.cc","source_file":"/src/tinyusb/test/fuzz/device/msc/src/fuzz.cc"}
```

similarly withhttps://introspector.oss-fuzz.com/api/project-summary?project=pcapplusplus