[lldb] Remove Python 2 compatibility code in embedded_interpreter.py

LLDB requires Python >= 3.8.

https://docs.python.org/3/whatsnew/3.0.html#library-changes
explains the renaming in Python 3.0.

Author: DavidSpickett

lldb/source/Interpreter/embedded_interpreter.py

@@ -1,9 +1,5 @@
 import sys
-
-if sys.version_info[0] < 3:
-    import __builtin__ as builtins
-else:
-    import builtins
+import builtins
 import code
 import lldb
 import traceback