Minimal fix for auto-importing node_modules in node12/nodenext (#46148)

Author: andrewbranch

src/compiler/moduleSpecifiers.ts

@@ -619,7 +619,7 @@ namespace ts.moduleSpecifiers {
         const nodeModulesDirectoryName = moduleSpecifier.substring(parts.topLevelPackageNameIndex + 1);
         const packageName = getPackageNameFromTypesPackageName(nodeModulesDirectoryName);
         // For classic resolution, only allow importing from node_modules/@types, not other node_modules
-        return getEmitModuleResolutionKind(options) !== ModuleResolutionKind.NodeJs && packageName === nodeModulesDirectoryName ? undefined : packageName;
+        return getEmitModuleResolutionKind(options) === ModuleResolutionKind.Classic && packageName === nodeModulesDirectoryName ? undefined : packageName;
 
         function tryDirectoryWithPackageJson(packageRootIndex: number) {
             const packageRootPath = path.substring(0, packageRootIndex);

tests/cases/fourslash/autoImport_node12_node_modules1.ts

@@ -0,0 +1,11 @@
+/// <reference path="fourslash.ts" />
+
+// @module: node12
+
+// @Filename: /node_modules/undici/index.d.ts
+//// export function request(): any;
+
+// @Filename: /index.mts
+//// request/**/
+
+verify.importFixModuleSpecifiers("", ["undici"]);