Try even harder to disable PDB generation

tools/run_tests/run_tests.py

@@ -479,7 +479,10 @@ if platform.system() == 'Windows':
   def make_jobspec(cfg, targets):
     extra_args = []
     if args.travis:
-      extra_args.extend(["/m", "/p:GenerateDebugInformation=false"])
+      # better do parallel compilation
+      extra_args.extend(["/m"])
+      # disable PDB generation: it's broken, and we don't need it during CI
+      extra_args.extend(["/p:GenerateDebugInformation=false", "/p:DebugInformationFormat:None"])
     return [
       jobset.JobSpec(['vsprojects\\build.bat', 
                       'vsprojects\\%s.sln' % target,