Balance mega tests, shorten some env names

buildroot/share/tests/STM32F103RC_btt-tests

@@ -0,0 +1,19 @@
+#!/usr/bin/env bash
+#
+# Build tests for STM32F103RC BigTreeTech (SKR Mini E3)
+#
+
+# exit on first failure
+set -e
+
+#
+# Build with the default configurations
+#
+restore_configs
+opt_set MOTHERBOARD BOARD_BTT_SKR_MINI_E3_V1_0
+opt_set SERIAL_PORT 1
+opt_set SERIAL_PORT_2 -1
+exec_test $1 $2 "BigTreeTech SKR Mini E3 - Basic Configuration"
+
+# clean up
+restore_configs