[infra] Update tools/test.py to not try to pass -m64 to aarch64 assembler in simarm64 mode

The arm64 compiler doesn't accept a -m64 argument.

Change-Id: I24dcd48862beff4becfd3627a43f4261b6ff2133
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/141894
Commit-Queue: Martin Kustermann <kustermann@google.com>
Reviewed-by: Daco Harkes <dacoharkes@google.com>
diff --git a/pkg/test_runner/lib/src/compiler_configuration.dart b/pkg/test_runner/lib/src/compiler_configuration.dart
index 9b2e6ba..f57b8ed 100644
--- a/pkg/test_runner/lib/src/compiler_configuration.dart
+++ b/pkg/test_runner/lib/src/compiler_configuration.dart
@@ -760,9 +760,9 @@
     String ccFlags;
     switch (_configuration.architecture) {
       case Architecture.x64:
-      case Architecture.simarm64:
         ccFlags = "-m64";
         break;
+      case Architecture.simarm64:
       case Architecture.ia32:
       case Architecture.simarm:
       case Architecture.arm: