fixed the tv.wcount and tv.s.len restoration logic upon compiliation failure

t/var-03.hcl

@@ -0,0 +1,31 @@
+## there are 8 local temporaries variables in the top-level context
+## the 8 temporaries defined inside the block expression are parked
+## at the top-level context. 'a' assigned before the block expression
+## is a global variable.
+
+a := 1234
+
+{
+	| a b c d |
+	| e f g h |
+	a := 10
+	b := 20
+	c := 30
+	d := 40
+	e := 50
+	f := 60
+	g := 70
+	h := 80
+		
+	if (/= a 10) { print "ERROR: a inside the block expression is not 10\n" } \
+	else { printf "OK: %d\n" a };
+}
+
+a := (a + 1)
+c := (sprintf "%d" a)
+
+if (/= a 1235) { printf "ERROR: a is not 1235\n" } \
+else { printf "OK: %d\n" a };
+
+if (nql? c "1235") { printf "ERROR: c is not \"1235\"\n" } \
+else { printf "OK: %s\n" c };