Revert "Increase analyzer cache size to 512MB."

This reverts commit 0256155.

Reason for revert: this change is obsolete; we now do caching outside the analyzer to make sure analyzer disk access is fast. So more likely we want to reduce the cache size to zero. Certainly, we don't want to increase it.

Original change's description:
> Increase analyzer cache size to 512MB.
> 
> I noticed earlier today that the cache looks to be to small for large internal apps, causing us to constantly reload summaries. This change fixes that, reducing build times significantly for large apps.
> 
> There is a larger issue here of the actual cache implementation though that should likely get resolved. We end up with several versions of each summary file in the cache until it fills up, so we will fill up the cache even on small apps today.
> 
> It is possible we should change how that works, instead of increasing this.
> 
> Fwiw, I see total ram consumption of almost exactly 1GB per worker after this change.
> 
> Change-Id: I0d8a06da72b86d44562819bc04f5ae5543610f0d
> Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/107360
> Reviewed-by: Konstantin Shcheglov <[email protected]>
> Reviewed-by: David Morgan <[email protected]>
> Commit-Queue: Jake Macdonald <[email protected]>

[email protected],[email protected],[email protected]

# Not skipping CQ checks because original CL landed > 1 day ago.

Change-Id: If00c0f9b8ee3fc177433df7c8d92731c2e5f0f9e
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/108140
Reviewed-by: David Morgan <[email protected]>
Reviewed-by: Konstantin Shcheglov <[email protected]>
Commit-Queue: David Morgan <[email protected]>

Author: davidmorgan

pkg/analyzer_cli/lib/src/build_mode.dart

@@ -62,7 +62,7 @@ class AnalyzerWorkerLoop extends AsyncWorkerLoop {
       {this.dartSdkPath})
       : super(connection: connection) {
     packageBundleCache = new WorkerPackageBundleCache(
-        resourceProvider, logger, 512 * 1024 * 1024);
+        resourceProvider, logger, 256 * 1024 * 1024);
   }
 
   factory AnalyzerWorkerLoop.sendPort(