fixup! refactor(@angular/build): encapsulate library build state in BuilderState and ExecutionResult

Author: alan-agius4

packages/angular/build/src/builders/library/builder-state.ts

@@ -150,6 +150,8 @@ export class BuilderState {
       }
     }
 
+    this.#pendingCompilationFiles.clear();
+
     return false;
   }
 

packages/angular/build/src/builders/library/pipeline/compilation.ts

@@ -61,7 +61,11 @@ export async function compileLibrary(
     let effectiveModifiedFiles = modifiedFiles;
     if (cached && cached.failedFiles.size > 0) {
       stylesheetBundler.invalidate(cached.failedFiles);
-      effectiveModifiedFiles = new Set([...(modifiedFiles ?? []), ...cached.failedFiles]);
+      const merged = new Set(modifiedFiles);
+      for (const file of cached.failedFiles) {
+        merged.add(file);
+      }
+      effectiveModifiedFiles = merged;
     }
 
     if (effectiveModifiedFiles && effectiveModifiedFiles.size > 0) {