Handle empty JSON files in fuzzer coverage task (follow up #1372). (#1384)
Handle empty JSON files in fuzzer coverage task (follow up #1372). (#1384)

Apparently, Go version was not crashing on this due to the way how JSON parsing
is implemented in Go. In Python, we have to be more explicit to handle this.
google/clusterfuzz,google/clusterfuzz,google/clusterfuzz,google/clusterfuzz,google/clusterfuzz,google/clusterfuzz,google/clusterfuzz,google/clusterfuzz