Backed out 4 changesets (bug 1621960) for causing Android bustages CLOSED TREE

Backed out changeset f36a95234a5f (bug 1621960)
Backed out changeset 0e4661c9061d (bug 1621960)
Backed out changeset 3e2cbe4dd777 (bug 1621960)
Backed out changeset d7eb101e5df7 (bug 1621960)

python/mach_commands.py

@@ -56,12 +56,12 @@ class MachCommands(MachCommandBase):
 
         # Note: subprocess requires native strings in os.environ on Windows.
         append_env = {
-            'PYTHONDONTWRITEBYTECODE': str('1'),
+            b'PYTHONDONTWRITEBYTECODE': str('1'),
         }
 
         if no_virtualenv:
             python_path = sys.executable
-            append_env['PYTHONPATH'] = os.pathsep.join(sys.path)
+            append_env[b'PYTHONPATH'] = os.pathsep.join(sys.path)
         else:
             self._activate_virtualenv()
             python_path = self.virtualenv_manager.python_path