Revert "Check detected npm path is existing"

This reverts commit 1fda3a4.

Author: mhegazy

src/server/typingsInstaller/nodeTypingsInstaller.ts

@@ -2,8 +2,7 @@
 
 namespace ts.server.typingsInstaller {
     const fs: {
-        appendFileSync(file: string, content: string): void;
-        existsSync(path: string): boolean;
+        appendFileSync(file: string, content: string): void
     } = require("fs");
 
     const path: {
@@ -33,12 +32,11 @@ namespace ts.server.typingsInstaller {
     /** Used if `--npmLocation` is not passed. */
     function getDefaultNPMLocation(processName: string) {
         if (path.basename(processName).indexOf("node") === 0) {
-            const npmPath = `"${path.join(path.dirname(process.argv[0]), "npm")}"`;
-            if (fs.existsSync(npmPath)) {
-                return npmPath;
-            }
+            return `"${path.join(path.dirname(process.argv[0]), "npm")}"`;
+        }
+        else {
+            return "npm";
         }
-        return "npm";
     }
 
     interface TypesRegistryFile {