KNOWNBUG test for $past for array type

Author: kroening

regression/verilog/system-functions/past5.desc

@@ -0,0 +1,9 @@
+KNOWNBUG
+past5.sv
+
+^EXIT=0$
+^SIGNAL=0$
+--
+^warning: ignoring
+--
+$past doesn't support the array.

regression/verilog/system-functions/past5.sv

@@ -0,0 +1,7 @@
+module main;
+
+  logic [31:0] mem[123];
+
+  assert property (##1 mem == $past(mem));
+
+endmodule