ci(l2): l2 prover (#1735)

**Motivation**

The CI is failing because we are downloading the latest version of sp1
(`4.0.0`), bumping up the version implies some changes and further
testing.

**Description**

Momentary solution: 
- download past version.

Linked to #1734

.github/workflows/ci_l2_prover.yaml

@@ -60,7 +60,7 @@ jobs:
       - name: RISC-V SP1 toolchain install
         run: |
           curl -L https://sp1.succinct.xyz | bash
-          ~/.sp1/bin/sp1up
+          ~/.sp1/bin/sp1up --version 3.0.0
       - name: Build prover and SP1's zkVM
         run: |
           cd crates/l2/prover

crates/l2/prover/tests/perf_zkvm.rs

@@ -61,7 +61,7 @@ async fn test_performance_sp1_zkvm() {
 async fn setup() -> (ProgramInput, Block) {
     let path = Path::new(concat!(env!("CARGO_MANIFEST_DIR"), "/../../../test_data"));
 
-    // Another use is genesis-execution-api.json in conjunction with chain.rlp(20 blocks not too loaded).
+    // Another use is genesis-execution-api.json in conjunction with chain.rlp(with 20 smaller blocks).
     let genesis_file_path = path.join("genesis-l2-old.json");
     // l2-loadtest.rlp has blocks with many txs.
     let chain_file_path = path.join("l2-loadtest.rlp");