Add support for SVA sequence concatenation ranges via verific

Signed-off-by: Clifford Wolf <clifford@clifford.at>

tests/sva/runtest.sh

@@ -35,6 +35,7 @@ generate_sby() {
 	cat <<- EOT
 		verific -import -extnets -all top
 		prep -top top
+		chformal -early -assume
 
 		[files]
 	EOT

tests/sva/sva_range.sv

@@ -0,0 +1,19 @@
+module top (
+	input clk,
+	input a, b, c, d
+);
+	default clocking @(posedge clk); endclocking
+
+	assert property (
+		a ##[*] b |=> c until ##[*] d
+	);
+
+`ifndef FAIL
+	assume property (
+		b |=> ##5 d
+	);
+	assume property (
+		b || (c && !d) |=> c
+	);
+`endif
+endmodule