Fix import_path circular dependency by splitting it out.

Use import thread_pool instead from, from is evil.

Fix poweroff.out path for ./trace-boot.

run-gdb

@@ -6,6 +6,7 @@ import subprocess
 import sys
 
 import common
+import lkmc.import_path
 from shell_helpers import LF
 
 class GdbTestcase:
@@ -33,7 +34,7 @@ class GdbTestcase:
         self.child.setecho(False)
         self.child.waitnoecho()
         self.child.expect(self.prompt)
-        test = common.import_path(test_script_path)
+        test = lkmc.import_path.import_path(test_script_path)
         exception = None
         try:
             test.test(self)