[backend]将testdata/下的测例替换为了赛方测试用例，更新了测试脚本

testdata/functional/27_while_test2.sy

@@ -0,0 +1,31 @@
+int FourWhile() {
+  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;
+        }
+        d = d - 1;
+      }
+      c = c + 1;
+    }
+    b = b - 2;
+  }
+  
+  return (a + (b + d) + c);
+}
+
+int main() {
+  return FourWhile();
+}