MBEDTLS_MEMORY_BACKTRACE is no longer included in the full config

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/tests/scripts/basic-build-test.sh b/tests/scripts/basic-build-test.sh
index 1b92e41..08c1410 100755
--- a/tests/scripts/basic-build-test.sh
+++ b/tests/scripts/basic-build-test.sh
@@ -68,7 +68,6 @@
 make clean
 cp "$CONFIG_H" "$CONFIG_BAK"
 scripts/config.py full
-scripts/config.py unset MBEDTLS_MEMORY_BACKTRACE
 make -j