fix: dedup pc by codehash for unique pc metric

[0xalpharush]

No description provided.

[ggrieco-tob]

Something is wrong in this PR, coverage is no longer increasingly monotonic: 🤔

⇾ fuzz: elapsed: 6m12s, calls: 1577938 (4214/sec), seq/s: 42, coverage: 13852, corpus: 93, failures: 0/15778, gas/s: 404891962
⇾ fuzz: elapsed: 6m15s, calls: 1590853 (4304/sec), seq/s: 42, coverage: 13135, corpus: 93, failures: 0/15907, gas/s: 406547696
⇾ fuzz: elapsed: 6m18s, calls: 1603635 (4259/sec), seq/s: 42, coverage: 14448, corpus: 93, failures: 0/16035, gas/s: 422164400
⇾ fuzz: elapsed: 6m21s, calls: 1616414 (4258/sec), seq/s: 42, coverage: 13668, corpus: 93, failures: 0/16162, gas/s: 425874519
⇾ fuzz: elapsed: 6m24s, calls: 1629197 (4260/sec), seq/s: 42, coverage: 13668, corpus: 93, failures: 0/16289, gas/s: 435137493