perf(@angular-devkit/build-angular): use Webpack's GC memory caching in watch mode

The GC caching mode will remove any unused cache entries after each rebuild. This prevents old modules from being retained indefinitely during long-lived development sessions.

(cherry picked from commit ef6996a)

Author: clydin

packages/angular_devkit/build_angular/src/webpack/configs/common.ts

@@ -483,7 +483,10 @@ export function getCommonConfig(wco: WebpackConfigOptions): Configuration {
         ...extraRules,
       ],
     },
-    cache: !!buildOptions.watch && !cachingDisabled,
+    cache: !!buildOptions.watch && !cachingDisabled && {
+      type: 'memory',
+      maxGenerations: 1,
+    },
     optimization: {
       minimizer: extraMinimizers,
       moduleIds: 'deterministic',