Retrieve the command line arguments from the fuzzer and save them for
later retrieval by `BasicTestingSetup` so that we gain extra flexibility
of passing any config options on the test command line, e.g.:
```
FUZZ=addrman ./src/test/fuzz/fuzz --checkaddrman=5
```
A fuzz test should call `MakeNoLogFileContext<>()` in its initialize
function in order to invoke the constructor of `BasicTestingSetup`,
which sets `gArgs`.