Initialize retctx,ctx before freeing the inner elements

[ret2libc]

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• I've added tests that prove my fix is effective or that my feature works (if possible)
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Detailed description

In rz_core_analysis_type_match retctx structure was initialized on the
stack only after a "goto out_function", where a field of that structure
was freed. When the goto path is taken, the field is not properly
initialized and it cause cause a crash of Rizin or have other effects.

Fixes: CVE-2021-4022

Test plan

...

Closing issues

Closes #2015