Add some tests

Copied from Efinix.

* fsm is broken
* latch and tribuf are not implemented yet
* memory maps to dram

tests/arch/gowin/run-test.sh

@@ -0,0 +1,20 @@
+#!/usr/bin/env bash
+set -e
+{
+echo "all::"
+for x in *.ys; do
+	echo "all:: run-$x"
+	echo "run-$x:"
+	echo "	@echo 'Running $x..'"
+	echo "	@../../../yosys -ql ${x%.ys}.log -w 'Yosys has only limited support for tri-state logic at the moment.' $x"
+done
+for s in *.sh; do
+	if [ "$s" != "run-test.sh" ]; then
+		echo "all:: run-$s"
+		echo "run-$s:"
+		echo "	@echo 'Running $s..'"
+		echo "	@bash $s"
+	fi
+done
+} > run-test.mk
+exec ${MAKE:-make} -f run-test.mk