Previously, some fuzzers were generating an excessive amount of debug
logging. This change explicitly disables debug logging for all fuzzers.
This allows higher test throughput and makes the logs easier to read
when fuzzing locally.
This is to differentiate between the upcoming `AllocatingMemoryStream`,
which automatically allocates memory as needed instead of operating on a
static memory area.
This generally seems like a better name, especially if we somehow also
need a better name for "read the entire buffer, but not the entire file"
somewhere down the line.
LibFuzzer documentation [1] states that all return values except for 0
and -1 are currently reserved for future use. -1 is a special return
value that causes LibFuzzer to not add a testing input to the testing
corpus, regardless of the code coverage that it causes.
[1] https://llvm.org/docs/LibFuzzer.html
