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/src/aot/compiler_options.ts

@@ -14,7 +14,6 @@ export interface AotCompilerOptions {
   translations?: string;
   missingTranslation?: MissingTranslationStrategy;
   enableLegacyTemplate?: boolean;
-  /** TODO(tbosch): remove this flag as it is always on in the new ngc */
   enableSummariesForJit?: boolean;
   preserveWhitespaces?: boolean;
   fullTemplateTypeCheck?: boolean;