perf(compiler): don’t emit summaries for jit by default

This re-adds the flag `enableSummariesForJit` to the compiler options
that already existed in Angular 4.

packages/compiler-cli/src/transformers/api.ts

@@ -144,6 +144,12 @@ export interface CompilerOptions extends ts.CompilerOptions {
 
   /** generate all possible generated files  */
   allowEmptyCodegenFiles?: boolean;
+
+  /**
+   * Whether to generate .ngsummary.ts files that allow to use AOTed artifacts
+   * in JIT mode. This is off by default.
+   */
+  enableSummariesForJit?: boolean;
 }
 
 export interface CompilerHost extends ts.CompilerHost {

packages/compiler-cli/src/transformers/program.ts

@@ -533,7 +533,7 @@ function getAotCompilerOptions(options: CompilerOptions): AotCompilerOptions {
     locale: options.i18nInLocale,
     i18nFormat: options.i18nInFormat || options.i18nOutFormat, translations, missingTranslation,
     enableLegacyTemplate: options.enableLegacyTemplate,
-    enableSummariesForJit: true,
+    enableSummariesForJit: options.enableSummariesForJit,
     preserveWhitespaces: options.preserveWhitespaces,
     fullTemplateTypeCheck: options.fullTemplateTypeCheck,
     allowEmptyCodegenFiles: options.allowEmptyCodegenFiles,