Add async_gsr minitest, to compare to async without GSR.

minitests/reg/async_gsr.v

diff --git a/minitests/reg/async_gsr.v b/minitests/reg/async_gsr.v
new file mode 100644
index 0000000..d0899e4
--- /dev/null
+++ b/minitests/reg/async_gsr.v
@@ -0,0 +1,8 @@
+module top(input clk, d, set, r, output reg q);
+    GSR gsr(.GSR(r));
+    always @(posedge clk or posedge set)
+           if (set)
+                q <= 1'b1;
+           else
+                q <= d;
+endmodule