make getTopmostPackageJSON public again, and update PackageExports test

javascript/ql/src/semmle/javascript/PackageExports.qll

@@ -28,7 +28,7 @@ private int countSlashes(string path) { result = count(path.splitAt("/")) - 1 }
  * There can be multiple results if the there exists multiple package.json that are equally deeply nested in the folder structure.
  * Results are limited to package.json files that are at most nested 2 directories deep.
  */
-private PackageJSON getTopmostPackageJSON() {
+PackageJSON getTopmostPackageJSON() {
   result =
     min(PackageJSON j |
       countSlashes(j.getFile().getRelativePath()) <= 3 and

javascript/ql/test/library-tests/PackageExports/tests.ql

@@ -3,9 +3,7 @@ import semmle.javascript.PackageExports as Exports
 
 query PackageJSON getTopmostPackageJSON() { result = Exports::getTopmostPackageJSON() }
 
-query DataFlow::Node getAValueExportedBy(PackageJSON json) {
-  result = Exports::getAValueExportedBy(json)
-}
+query DataFlow::Node getALibraryInputParameter() { result = Exports::getALibraryInputParameter() }
 
 query DataFlow::Node getAnExportedValue(Module mod, string name) {
   result = mod.getAnExportedValue(name)