fix(@ngtools/webpack): remove saving Angular compiler in JIT watch mode

The Angular compiler is now only used on the first JIT build to analyze the deprecated string form lazy routes. As a result, there is no need to save the previous compiler instance.

packages/ngtools/webpack/src/ivy/plugin.ts

@@ -569,7 +569,6 @@ export class AngularWebpackPlugin {
         rootNames,
         compilerOptions,
         host,
-        this.ngtscNextProgram,
       );
       const angularCompiler = angularProgram.compiler;
       const pendingAnalysis = angularCompiler.analyzeAsync().then(() => {
@@ -586,10 +585,6 @@ export class AngularWebpackPlugin {
         return innerFileEmitter(file);
       };
 
-      if (this.watchMode) {
-        this.ngtscNextProgram = angularProgram;
-      }
-
       return {
         fileEmitter: analyzingFileEmitter,
         builder,