fix(language-service): Remove tsserverlibrary from rollup globals

This PR removes `tsserverlibrary` from rollup globals since the symbol
should not appear by the time rollup is invoked. `tsserverlibrary` is
used for types only, so the import statement should not be emitted by
tsc.

packages/language-service/bundles/BUILD.bazel

@@ -7,7 +7,6 @@ ls_rollup_bundle(
         "fs": "fs",
         "path": "path",
         "typescript": "ts",
-        "typescript/lib/tsserverlibrary": "tsserverlibrary",
     },
     license_banner = "banner.js.txt",
     visibility = ["//packages/language-service:__pkg__"],

packages/language-service/src/ts_plugin.ts

@@ -6,15 +6,16 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import * as ts from 'typescript/lib/tsserverlibrary';
+import * as ts from 'typescript'; // used as value, passed in by tsserver at runtime
+import * as tss from 'typescript/lib/tsserverlibrary'; // used as type only
 
 import {createLanguageService} from './language_service';
 import {Completion, Diagnostic, DiagnosticMessageChain} from './types';
 import {TypeScriptServiceHost} from './typescript_host';
 
-const projectHostMap = new WeakMap<ts.server.Project, TypeScriptServiceHost>();
+const projectHostMap = new WeakMap<tss.server.Project, TypeScriptServiceHost>();
 
-export function getExternalFiles(project: ts.server.Project): string[]|undefined {
+export function getExternalFiles(project: tss.server.Project): string[]|undefined {
   const host = projectHostMap.get(project);
   if (host) {
     const externalFiles = host.getTemplateReferences();
@@ -63,7 +64,7 @@ function diagnosticToDiagnostic(d: Diagnostic, file: ts.SourceFile): ts.Diagnost
   return result;
 }
 
-export function create(info: ts.server.PluginCreateInfo): ts.LanguageService {
+export function create(info: tss.server.PluginCreateInfo): ts.LanguageService {
   const oldLS: ts.LanguageService = info.languageService;
   const proxy: ts.LanguageService = Object.assign({}, oldLS);
   const logger = info.project.projectService.logger;