add: tests for zero-parser.

sysy_sets/28_while_test3.sy

@@ -0,0 +1,55 @@
+int g;
+int h;
+int f;
+int e;
+int EightWhile() {
+  int a;
+  a = 5;
+  int b;
+  int c;
+  b = 6;
+  c = 7;
+  int d;
+  d = 10;
+  while (a < 20) {
+    a = a + 3;
+    while(b < 10){
+      b = b + 1;
+      while(c == 7){
+        c = c - 1;
+        while(d < 20){
+          d = d + 3;
+          while(e > 1){
+            e = e-1;
+            while(f > 2){
+              f = f -2;
+              while(g < 3){
+                g = g +10;
+                while(h < 10){
+                  h = h + 8;
+                }
+                h = h-1;
+              }
+              g = g- 8;
+            }
+            f = f + 1;
+          }
+          e = e + 1;
+        }
+        d = d - 1;
+      }
+      c = c + 1;
+    }
+    b = b - 2;
+  }
+  
+  return (a + (b + d) + c)-(e + d - g + h);
+}
+
+int main() {
+  g = 1;
+  h = 2;
+  e = 4;
+  f = 6;
+  return EightWhile();
+}