Re-add require cache clearing (#7674)

packages/next/build/static-checker.ts

@@ -7,6 +7,18 @@ export default function worker(
   try {
     const { serverBundle, runtimeEnvConfig } = options || ({} as any)
     const isStatic = isPageStatic(serverBundle, runtimeEnvConfig)
+
+    // clear require.cache to prevent running out of memory
+    // since the cache is persisted by default
+    Object.keys(require.cache).map(modId => {
+      const mod = require.cache[modId]
+      delete require.cache[modId]
+      if (mod.parent) {
+        const idx = mod.parent.children.indexOf(mod)
+        mod.parent.children.splice(idx, 1)
+      }
+    })
+
     callback(null, { isStatic })
   } catch (error) {
     callback(error)