Fix null dereference of angularPlugin.

PiperOrigin-RevId: 295670447

internal/tsc_wrapped/tsc_wrapped.ts

diff --git a/internal/tsc_wrapped/tsc_wrapped.ts b/internal/tsc_wrapped/tsc_wrapped.ts
index 848ba2e..659a91a 100644
--- a/internal/tsc_wrapped/tsc_wrapped.ts
+++ b/internal/tsc_wrapped/tsc_wrapped.ts
@@ -360,7 +360,9 @@
 
     // Wrap host only needed until after Ivy cleanup
     // TODO(alexeagle): remove after ngsummary and ngfactory files eliminated
-    compilerHost = angularPlugin!.wrapHost!(files, compilerHost);
+    if (angularPlugin) {
+      compilerHost = angularPlugin.wrapHost!(files, compilerHost);
+    }
   }