Tweak tests, consolidate pins target validation (#21254)

buildroot/tests/STM32F103RE_btt

@@ -0,0 +1,19 @@
+#!/usr/bin/env bash
+#
+# Build tests for STM32F103RE BigTreeTech (SKR E3 DIP v1.0)
+#
+
+# exit on first failure
+set -e
+
+#
+# Build with the default configurations
+#
+restore_configs
+opt_set MOTHERBOARD BOARD_BTT_SKR_E3_DIP \
+        SERIAL_PORT 1 SERIAL_PORT_2 -1 \
+        X_DRIVER_TYPE TMC2209 Y_DRIVER_TYPE TMC2130
+exec_test $1 $2 "BTT SKR E3 DIP 1.0 | Mixed TMC Drivers" "$3"
+
+# clean up
+restore_configs