gh-146238: add missing tests for 'e' type code in test_buffer.py

This amends e79fd60.  I'll not fix this for 'F'/'D' complex types as
they might be removed.

Author: skirpichev

Lib/test/test_buffer.py

@@ -143,7 +143,7 @@ def native_type_range(fmt):
 # Format codes supported by array.array
 ARRAY = NATIVE.copy()
 for k in NATIVE:
-    if not k in "bBhHiIlLfd":
+    if not k in "bBhHiIlLefd":
         del ARRAY[k]
 
 BYTEFMT = NATIVE.copy()