Upgrade capstone to use python3

[twizmwazin]

Upstream has ended python2 support. When removing python2 compatibility code, it was noticed that oss-fuzz was still utilizing this support. This fixes that by moving to a supported version of python3.

See this PR: capstone-engine/capstone#2378

[google-cla]

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[github-actions]

twizmwazin is a new contributor to projects/capstone. The PR must be approved by known contributors before it can be merged. The past contributors are: kabeor, vanhauser-thc, inferno-chromium, catenacyber, StalkR, devtty1er, Dor1s

[XVilka]

twizmwazin is a new contributor to projects/capstone. The PR must be approved by known contributors before it can be merged. The past contributors are: kabeor, vanhauser-thc, inferno-chromium, catenacyber, StalkR, devtty1er, Dor1s

@kabeor could you please take a look?

[maflcko]

CI failed with: /src/build.sh: ./test_corpus.py: /usr/bin/python: bad interpreter: No such file or directory

[kabeor]

Hello, we have merged the relevant PR upstream, so we hope to rerun it to apply the patched code, thanks.

[Rot127]

@maflcko Could you please trigger the CI again?

[maflcko]

I am not a maintainer here. Maybe @DavidKorczynski can help?

[XVilka]

@kabeor you probably need to approve it again

[Rot127]

@DavidKorczynski ping

[DavidKorczynski]

retriggered CI