Fuzz blockers

The following nodes represent call sites where fuzz blockers occur.

Amount of callsites blocked	Calltree index	Parent function	Callsite	Largest blocked function
2	2	ijson.get_backend	call site: 00002	io.BytesIO

Fuzzer calltree


         ...fuzz_all.TestOneInput

[function] [call site] 00000


           ijson.get_backend

[function] [call site] 00001


             importlib.import_module

[function] [call site] 00002


           io.BytesIO

[function] [call site] 00003


           backend.parse

[function] [call site] 00004