[flutter_tools] ensure processUtils reports exit code in ProcessExceptions (#136672)

Help to debug situations like: https://github.com/flutter/flutter/issues/135982

packages/flutter_tools/lib/src/base/process.dart

@@ -277,7 +277,7 @@ class _DefaultProcessUtils implements ProcessUtils {
       _logger.printTrace(runResult.toString());
       if (throwOnError && runResult.exitCode != 0 &&
           (allowedFailures == null || !allowedFailures(runResult.exitCode))) {
-        runResult.throwException('Process exited abnormally:\n$runResult');
+        runResult.throwException('Process exited abnormally with exit code ${runResult.exitCode}:\n$runResult');
       }
       return runResult;
     }
@@ -341,7 +341,7 @@ class _DefaultProcessUtils implements ProcessUtils {
         _logger.printTrace(runResult.toString());
         if (throwOnError && runResult.exitCode != 0 &&
             (allowedFailures == null || !allowedFailures(exitCode))) {
-          runResult.throwException('Process exited abnormally:\n$runResult');
+          runResult.throwException('Process exited abnormally with exit code $exitCode:\n$runResult');
         }
         return runResult;
       }
@@ -407,7 +407,7 @@ class _DefaultProcessUtils implements ProcessUtils {
     }
 
     if (failedExitCode && throwOnError) {
-      String message = 'The command failed';
+      String message = 'The command failed with exit code ${runResult.exitCode}';
       if (verboseExceptions) {
         message = 'The command failed\nStdout:\n${runResult.stdout}\n'
             'Stderr:\n${runResult.stderr}';

packages/flutter_tools/test/general.shard/base/process_test.dart

@@ -33,7 +33,10 @@ void main() {
         exitCode: 1,
       ));
 
-      expect(() async => processUtils.run(<String>['false'], throwOnError: true), throwsProcessException());
+      expect(
+        () async => processUtils.run(<String>['false'], throwOnError: true),
+        throwsProcessException(message: 'Process exited abnormally with exit code 1'),
+      );
     });
   });
 

packages/flutter_tools/test/integration.shard/plist_parser_test.dart

@@ -123,7 +123,7 @@ void main() {
     expect(logger.statusText, contains('Property List error: Unexpected character \x01 at line 1 / '
       'JSON error: JSON text did not start with array or object and option to allow fragments not '
       'set. around line 1, column 0.\n'));
-    expect(logger.errorText, 'ProcessException: The command failed\n'
+    expect(logger.errorText, 'ProcessException: The command failed with exit code 1\n'
               '  Command: /usr/bin/plutil -convert xml1 -o - ${file.absolute.path}\n');
   }, skip: !platform.isMacOS); // [intended] requires macos tool chain.
 
@@ -185,7 +185,7 @@ void main() {
     expect(logger.statusText, contains('foo.plist: Property List error: Unexpected character \x01 '
       'at line 1 / JSON error: JSON text did not start with array or object and option to allow '
       'fragments not set. around line 1, column 0.\n'));
-    expect(logger.errorText, equals('ProcessException: The command failed\n'
+    expect(logger.errorText, equals('ProcessException: The command failed with exit code 1\n'
       '  Command: /usr/bin/plutil -replace CFBundleIdentifier -string dev.flutter.fake foo.plist\n'));
   }, skip: !platform.isMacOS); // [intended] requires macos tool chain.