autoname: add testcase with $-prefix-ed port

tests/various/autoname.ys

@@ -0,0 +1,19 @@
+read_ilang <<EOT
+autoidx 2
+module \top
+  wire output 3 $y
+  wire input 1 \a
+  wire input 2 \b
+  cell $and \b_$and_B
+    parameter \A_SIGNED 0
+    parameter \A_WIDTH 1
+    parameter \B_SIGNED 0
+    parameter \B_WIDTH 1
+    parameter \Y_WIDTH 1
+    connect \A \a
+    connect \B \b
+    connect \Y $y
+  end
+end
+EOT
+autoname