Remove unused imports in tests (GH-14518) (GH-14520)

(cherry picked from commit 8f4ef3b019ce380022018587571b0f970e668de3)
diff --git a/Lib/test/test_cmath.py b/Lib/test/test_cmath.py
index a00185f..668f27c 100644
--- a/Lib/test/test_cmath.py
+++ b/Lib/test/test_cmath.py
@@ -6,7 +6,7 @@
 from cmath import phase, polar, rect, pi
 import platform
 import sys
-import sysconfig
+
 
 INF = float('inf')
 NAN = float('nan')