fix(ci): 在 cd 上游源码前解析 SCRIPT_DIR

相对路径 BASH_SOURCE 在进入 rocksdb 临时目录后失效，导致 patch 步骤找不到 .github/scripts。

Author: rockeet

.github/scripts/build_upstream_rocksdb.sh

@@ -30,8 +30,9 @@ fi
 # SIGILL on run hosts without AVX-512. Override e.g. PORTABLE=skylake-avx512.
 export DEBUG_LEVEL="${DEBUG_LEVEL:-0}"
 export PORTABLE="${PORTABLE:-haswell}"
-cd "$SRC_DIR"
+# Resolve script dir before cd: BASH_SOURCE may be a relative path.
 SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+cd "$SRC_DIR"
 python3 "$SCRIPT_DIR/patch_db_bench_time.py" "$SRC_DIR/tools/db_bench_tool.cc"
 echo "Building upstream rocksdb with PORTABLE=${PORTABLE} DEBUG_LEVEL=${DEBUG_LEVEL}"
 make db_bench memtablerep_bench -j"$(nproc)" DEBUG_LEVEL="$DEBUG_LEVEL" PORTABLE="$PORTABLE"