module: CJS loader re-stats the same missing paths within one require tree

The CommonJS loader keeps a per-require-tree `statCache` (in `lib/internal/modules/cjs/loader.js`) to avoid re-`stat`-ing the same path while resolving a module tree. Today it only caches successful stats. Negative results (e.g. `-ENOENT`) fall through the cache and are re-probed every time the same missing path is looked up again within the same top-level `require`. ```js // lib/internal/modules/cjs/loader.js — stat() const result = internalFsBinding.internalModuleStat(filename); if (statCache !== null && result >= 0) { // Only set cache when `internalModuleStat(filename)` succeeds. statCache.set(filename, result); } ``` Failed probes are extremely common during resolution, and the same misses recur across sibling and descendant modules: - **`tryExtensions`** resolves an extensionless specifier (e.g. `require('./helper')`) by `stat`-ing each candidate in order: `./helper.js`, then `./helper.json`, then `./helper.node` until one exists. Every extension tried before the real one is a miss. - **Bare specifiers** (`require('foo')`) walk the `node_modules` chain upward: `…/a/b/node_modules`, `…/a/node_modules`, `…/node_modules`. Most of those parent directories don't exist, so each is a negative stat, and every bare require in the tree re-walks the same non-existent ancestors. Because negatives aren't cached, these misses are re-`stat`-ed repeatedly within a single resolution pass.