bpo-33656: Move pyshell ctypes import inside try block. (GH-9858)

A Windows build with _tkinter, tkinter, and idlelib
but without ctypes is unlikely but apparently possible.
(cherry picked from commit d274afb)

Co-authored-by: Terry Jan Reedy <tjreedy@udel.edu>

Lib/idlelib/pyshell.py

@@ -12,11 +12,11 @@
 # Valid arguments for the ...Awareness call below are defined in the following.
 # https://msdn.microsoft.com/en-us/library/windows/desktop/dn280512(v=vs.85).aspx
 if sys.platform == 'win32':
-    import ctypes
-    PROCESS_SYSTEM_DPI_AWARE = 1
     try:
+        import ctypes
+        PROCESS_SYSTEM_DPI_AWARE = 1
         ctypes.OleDLL('shcore').SetProcessDpiAwareness(PROCESS_SYSTEM_DPI_AWARE)
-    except (AttributeError, OSError):
+    except (ImportError, AttributeError, OSError):
         pass
 
 import tkinter.messagebox as tkMessageBox