mshv_root_tests: save dmesg at the correct place

dmesg logs are not saved for some error paths which throw before
reaching the code that saves the logs.

Move this code to the correct place in verify_mshv_stress_vm_create.

microsoft/testsuites/mshv/mshv_root_tests.py

@@ -124,6 +124,7 @@ class MshvHostTestSuite(TestSuite):
                 self._send_subtest_msg(
                     result, environment, test_name, TestStatus.FAILED, repr(e)
                 )
+        self._save_dmesg_logs(node, log_path)
         assert_that(failures).is_equal_to(0)
         return
 
@@ -183,10 +184,6 @@ class MshvHostTestSuite(TestSuite):
             disk_img_file = node.working_path / f"VM{i}_{self.DISK_IMG_NAME}"
             node.tools[Rm].remove_file(str(disk_img_file))
 
-        dmesg_str = node.tools[Dmesg].get_output()
-        dmesg_path = log_path / f"dmesg_{times}_{cpus_per_vm}_{mem_per_vm_mb}"
-        with open(str(dmesg_path), "w") as f:
-            f.write(dmesg_str)
         assert_that(failures).is_equal_to(0)
 
     def _send_subtest_msg(
@@ -207,3 +204,9 @@ class MshvHostTestSuite(TestSuite):
         )
 
         notifier.notify(subtest_msg)
+
+    def _save_dmesg_logs(self, node: Node, log_path: Path) -> None:
+        dmesg_str = node.tools[Dmesg].get_output()
+        dmesg_path = log_path / "dmesg"
+        with open(str(dmesg_path), "w") as f:
+            f.write(dmesg_str)