Normalize whitespace in stacktrace golden (#4220)

diff --git a/test/embedding/embedding_test.dart b/test/embedding/embedding_test.dart
index 2a15ed1..20c94d1 100644
--- a/test/embedding/embedding_test.dart
+++ b/test/embedding/embedding_test.dart
@@ -474,7 +474,7 @@
         r'   ',
       )
       .replaceAll(
-        RegExp(r' [\d]+:[\d]+ ', multiLine: true),
+        RegExp(r' [\d]+:[\d]+ +', multiLine: true),
         r' $LINE:$COL ',
       )
       .replaceAll(
diff --git a/test/testdata/goldens/embedding/embedding_test/logfile is written with --verbose and on unexpected exceptions.txt b/test/testdata/goldens/embedding/embedding_test/logfile is written with --verbose and on unexpected exceptions.txt
index dc9a51d..25d1baa 100644
--- a/test/testdata/goldens/embedding/embedding_test/logfile is written with --verbose and on unexpected exceptions.txt
+++ b/test/testdata/goldens/embedding/embedding_test/logfile is written with --verbose and on unexpected exceptions.txt
@@ -296,17 +296,17 @@
 
 $ tool/test-bin/pub_command_runner.dart pub fail
 [E] Bad state: Pub has crashed
-[E]  tool/test-bin/pub_command_runner.dart $LINE:$COL   ThrowingCommand.runProtected
-[E] package:pub/src/command.dart $LINE:$COL   PubCommand.run.<fn>
+[E]  tool/test-bin/pub_command_runner.dart $LINE:$COL ThrowingCommand.runProtected
+[E] package:pub/src/command.dart $LINE:$COL PubCommand.run.<fn>
 [E] dart:async   new Future.sync
-[E] package:pub/src/utils.dart $LINE:$COL   captureErrors.wrappedCallback
+[E] package:pub/src/utils.dart $LINE:$COL captureErrors.wrappedCallback
 [E] dart:async   runZonedGuarded
-[E] package:pub/src/utils.dart $LINE:$COL   captureErrors
-[E] package:pub/src/command.dart $LINE:$COL   PubCommand.run
-[E] package:args/command_runner.dart $LINE:$COL   CommandRunner.runCommand
-[E]  tool/test-bin/pub_command_runner.dart $LINE:$COL  Runner.runCommand
-[E]  tool/test-bin/pub_command_runner.dart $LINE:$COL   Runner.run
-[E]  tool/test-bin/pub_command_runner.dart $LINE:$COL  main
+[E] package:pub/src/utils.dart $LINE:$COL captureErrors
+[E] package:pub/src/command.dart $LINE:$COL PubCommand.run
+[E] package:args/command_runner.dart $LINE:$COL CommandRunner.runCommand
+[E]  tool/test-bin/pub_command_runner.dart $LINE:$COL Runner.runCommand
+[E]  tool/test-bin/pub_command_runner.dart $LINE:$COL Runner.run
+[E]  tool/test-bin/pub_command_runner.dart $LINE:$COL main
 [E] This is an unexpected error. The full log and other details are collected in:
 [E] 
 [E]    $SANDBOX/cache/log/pub_log.txt
@@ -337,17 +337,17 @@
 FINE: Pub 3.1.2+3
 ERR : Bad state: Pub has crashed
 FINE: Exception type: StateError
-ERR : tool/test-bin/pub_command_runner.dart $LINE:$COL   ThrowingCommand.runProtected
-   | package:pub/src/command.dart $LINE:$COL   PubCommand.run.<fn>
+ERR : tool/test-bin/pub_command_runner.dart $LINE:$COL ThrowingCommand.runProtected
+   | package:pub/src/command.dart $LINE:$COL PubCommand.run.<fn>
    | dart:async   new Future.sync
-   | package:pub/src/utils.dart $LINE:$COL   captureErrors.wrappedCallback
+   | package:pub/src/utils.dart $LINE:$COL captureErrors.wrappedCallback
    | dart:async   runZonedGuarded
-   | package:pub/src/utils.dart $LINE:$COL   captureErrors
-   | package:pub/src/command.dart $LINE:$COL   PubCommand.run
-   | package:args/command_runner.dart $LINE:$COL   CommandRunner.runCommand
-   | tool/test-bin/pub_command_runner.dart $LINE:$COL  Runner.runCommand
-   | tool/test-bin/pub_command_runner.dart $LINE:$COL   Runner.run
-   | tool/test-bin/pub_command_runner.dart $LINE:$COL  main
+   | package:pub/src/utils.dart $LINE:$COL captureErrors
+   | package:pub/src/command.dart $LINE:$COL PubCommand.run
+   | package:args/command_runner.dart $LINE:$COL CommandRunner.runCommand
+   | tool/test-bin/pub_command_runner.dart $LINE:$COL Runner.runCommand
+   | tool/test-bin/pub_command_runner.dart $LINE:$COL Runner.run
+   | tool/test-bin/pub_command_runner.dart $LINE:$COL main
 ERR : This is an unexpected error. The full log and other details are collected in:
    | 
    |   $SANDBOX/cache/log/pub_log.txt