Don't drop unsupported instructions from the CFG

[geo2a]

On encountering an unrecognized instruction when building the CFG, Tealer reports it as "Not found" on stdout, but does not include it into the CFG. I find it rather confusing, since no error is reported and the graph just skips the unsupported instruction.

I see two alternative ways of correcting this behavior:

• Rise an exception on encountering an unsupported instruction
• Implemented in this PR Proceed normally, but include the unsupported instruction into the CFG and mark it appropriately.

Example

Consider TEALv6 program that uses the acct_params_get instruction, which is not supported by Tealer:

#pragma version 6
int 0
acct_params_get AcctBalance
!
// a comment
assert
int 0
==

Output before the patch

We see that line 3 is dropped from the CFG. This is the behavior of Tealer on both main and dev.

Output after the patch

Now line 3 is not dropped, but the instruction is marked as "UNSUPPOTED". Line 5 that contains a comment is still dropped, as expected.

[geo2a]

I suspect that the CI fails due to some permission issues. I've run the tests and the checks outlined in the contribution guidelines locally with no issues.

[ehildenb]

@montyly can you have a look here? We want to contribute, but we are unsure how to proceed with the permissions issues.

[0xalpharush]

The tests were failing do to some type annotations (in pytest IIRC) not being natively available in python 3.6. We've been migrating to python 3.8 across our repos recently to address this. All passing here (aside from some mypy error I haven't figured out yet): https://github.com/crytic/tealer/pull/79

[montyly]

This PR was merged with #79. Thanks @geo2a

[geo2a]

Thanks @montyly!