fix(compiler-cli): use the oldProgram option in watch mode (#21364)

The performCompilation() is always called with an undefined oldProgram option (even in watch mode).
This was regression introduced in: https://github.com/angular/angular/commit/957be960d28f4f6e8df695d98e2ed117e8451f88

Partial fix, discovered in: #21361

PR Close #21364

packages/compiler-cli/src/perform_watch.ts

@@ -200,7 +200,7 @@ export function performWatchCompilation(host: PerformWatchHost):
       rootNames: cachedOptions.rootNames,
       options: cachedOptions.options,
       host: cachedCompilerHost,
-      oldProgram: cachedProgram,
+      oldProgram: oldProgram,
       emitCallback: host.createEmitCallback(cachedOptions.options)
     });