Revert "Don't scan require calls in Browserify/Webpack bundles."

This reverts commit 99cb96fcf7.

Webpack already avoids this problem by transforming `require` to
`__webpack_require__`, and Browserify bundles can use something like
https://www.npmjs.com/package/derequire to rewrite ``require` calls to
avoid confusing other tools. False positives are acceptable, and we can
measure/mitigate the performance consequences in any number of ways.

Fixes #6427.
Fixes #6430.

tools/isobuild/js-analyze.js

@@ -83,10 +83,6 @@ export function findImportedModuleIdentifiers(source, hash) {
       while (left < right && end < possibleIndexes[right - 1]) --right;
 
       if (left < right) {
-        if (isFunctionWithParameter(node, "require")) {
-          return;
-        }
-
         let id = getRequiredModuleId(node);
         if (typeof id === "string") {
           identifiers[id] = node;
@@ -129,18 +125,6 @@ function isNode(value) {
     && typeof value.end === "number";
 }
 
-function isFunctionWithParameter(node, name) {
-  if (node.type === "FunctionExpression" ||
-      node.type === "FunctionDeclaration" ||
-      node.type === "ArrowFunctionExpression") {
-    return node.params.some(
-      param =>
-        param.type === "Identifier" &&
-        param.name === name
-    );
-  }
-}
-
 function getRequiredModuleId(node) {
   if (node.type === "CallExpression" &&
       node.callee.type === "Identifier" &&