[analyzer cli] Don't ask for errors on the same file several times

```
$ out/ReleaseX64/dart pkg/front_end/tool/benchmarker.dart --silent --iterations=10 --gcs=5 --snapshot=pkg/analyzer_cli/bin/analyzer.aot.1 --snapshot=pkg/analyzer_cli/bin/analyzer.aot.2 --arguments="/tmp/extracted_compile_dart_compile/"
Will now run 10 iterations with 2 snapshots.
..............................

Comparing snapshot #1 (analyzer.aot.1) with snapshot #2 (analyzer.aot.2)
msec task-clock:u: -7.7915% +/- 1.2399% (-851.98 +/- 135.58) (10934.74 -> 10082.76)

page-faults:u: -1.7454% +/- 1.1131% (-2457.20 +/- 1566.98) (140777.80 -> 138320.60)
cycles:u: -5.6010% +/- 1.2559% (-2318118149.50 +/- 519783195.96) (41387425609.80 -> 39069307460.30)
instructions:u: -7.0130% +/- 0.5970% (-3636754009.20 +/- 309595118.25) (51857207312.90 -> 48220453303.70)
branch-misses:u: -6.2869% +/- 4.5941% (-9795625.90 +/- 7158088.69) (155810738.90 -> 146015113.00)
seconds time elapsed: -7.7884% +/- 1.2389% (-0.85 +/- 0.14) (10.94 -> 10.09)
seconds user: -6.0176% +/- 1.4855% (-0.59 +/- 0.14) (9.75 -> 9.16)
seconds sys: -22.3326% +/- 4.4197% (-0.27 +/- 0.05) (1.19 -> 0.92)
Comparing GC:
No change in combined time.
```
Change-Id: Ibb34829a42770c22567bc1399bcf7eaf26201e99
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/449121
Reviewed-by: Johnni Winther <[email protected]>
Commit-Queue: Jens Johansen <[email protected]>

Author: jensjoha

pkg/analyzer_cli/lib/src/analyzer_impl.dart

@@ -47,13 +47,16 @@ class AnalyzerImpl {
   /// specified the "--package-warnings" option.
   String? _selfPackageName;
 
+  final Set<String> gotErrorsFor;
+
   AnalyzerImpl(
     this.analysisOptions,
     this.analysisDriver,
     this.libraryFile,
     this.options,
     this.stats,
     this.startTime,
+    this.gotErrorsFor,
   );
 
   void addCompilationUnitSource(
@@ -134,9 +137,11 @@ class AnalyzerImpl {
   /// Fills [errorsResults] using [files].
   Future<void> prepareErrors() async {
     for (var path in files) {
-      var errorsResult = await analysisDriver.getErrors(path);
-      if (errorsResult is ErrorsResult) {
-        errorsResults.add(errorsResult);
+      if (gotErrorsFor.add(path)) {
+        var errorsResult = await analysisDriver.getErrors(path);
+        if (errorsResult is ErrorsResult) {
+          errorsResults.add(errorsResult);
+        }
       }
     }
   }

pkg/analyzer_cli/lib/src/driver.dart

@@ -262,6 +262,7 @@ class Driver implements CommandLineStarter {
 
       // Analyze the libraries.
       var pathContext = resourceProvider.pathContext;
+      final gotErrorsFor = <String>{};
       for (var path in filesToAnalyze) {
         if (file_paths.isAnalysisOptionsYaml(pathContext, path)) {
           var fileResult = analysisDriver.currentSession.getFile(path);
@@ -397,7 +398,12 @@ class Driver implements CommandLineStarter {
 
           final kind = file.kind;
           if (kind is LibraryFileKind) {
-            var status = await _runAnalyzer(file, options, formatter);
+            var status = await _runAnalyzer(
+              file,
+              options,
+              formatter,
+              gotErrorsFor,
+            );
             allResult = allResult.max(status);
             analyzedFiles.addAll(kind.files);
           } else if (kind is PartFileKind) {
@@ -468,6 +474,7 @@ class Driver implements CommandLineStarter {
     FileState file,
     CommandLineOptions options,
     ErrorFormatter formatter,
+    Set<String> gotErrorsFor,
   ) {
     var startTime = currentTimeMillis;
     final analysisDriver = this.analysisDriver!;
@@ -481,6 +488,7 @@ class Driver implements CommandLineStarter {
       options,
       stats,
       startTime,
+      gotErrorsFor,
     );
     return analyzer.analyze(formatter);
   }