Add some simple SVA test cases for future Verific work

tests/sva/basic01.sv

@@ -0,0 +1,12 @@
+module top (input logic clock, ctrl);
+	logic read = 0, write = 0, ready = 0;
+
+	always @(posedge clock) begin
+		read <= !ctrl;
+		write <= ctrl;
+		ready <= write;
+	end
+	
+	a_rw: assert property ( @(posedge clock) !(read && write) );
+	a_wr: assert property ( @(posedge clock) write |-> ready );
+endmodule