Handle the case where public functions with the same implementation are merged

[sifislag]

In optimized contracts, public functions with the same implementation can sometimes get merged. Gigahorse used to just infer the one, and this pr fixes it:

• We attempt to clone a public function entry block that is shared between different methods.
• If this entry block is a JUMPI block (very often), we transform it to a JUMP block by adding a direct jump in the middle of it, and breaking it up to two blocks. This way the cloner can work.

[github-actions]

Test Results (Souffle 2.3)

62 tests  +1   62 ✅ +1   48m 41s ⏱️ +24s
 1 suites ±0    0 💤 ±0 
 1 files   ±0    0 ❌ ±0 

Results for commit 482ddb3. ± Comparison against base commit fbc34bf.

[github-actions]

Test Results (Souffle 2.4)

62 tests  +1   62 ✅ +1   54m 27s ⏱️ + 6m 7s
 1 suites ±0    0 💤 ±0 
 1 files   ±0    0 ❌ ±0 

Results for commit 482ddb3. ± Comparison against base commit fbc34bf.