long fuzz tests ci on btree changes

The idea is simple, if you modify the btree, we should verify fuzz tests
with long number of iterations to decrease the chance of a regression

.github/workflows/long_fuzz_tests_btree.yml

@@ -0,0 +1,44 @@
+name: Run long fuzz tests on Btree
+
+on:
+  push:
+    paths:
+      - 'core/storage/btree.rs'
+  pull_request:
+    paths:
+      - 'core/storage/btree.rs'
+
+jobs:
+  run-long-tests:
+    runs-on: ubuntu-latest
+    timeout-minutes: 0 
+    
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v3
+        with:
+          fetch-depth: 0 
+      
+      - name: Set up Rust
+        uses: actions-rs/toolchain@v1
+        with:
+          profile: minimal
+          toolchain: stable
+          override: true
+          components: rustfmt, clippy
+      
+      - name: Cache dependencies
+        uses: actions/cache@v3
+        with:
+          path: |
+            ~/.cargo/registry
+            ~/.cargo/git
+            target
+          key: ${{ runner.os }}-cargo-${{ hashFiles('**/Cargo.lock') }}
+          restore-keys: |
+            ${{ runner.os }}-cargo-
+      
+      - name: Run ignored long tests
+        run: cargo test -- --ignored fuzz_long
+        env:
+          RUST_BACKTRACE: 1