[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/31_while_if_test1.sy

@@ -0,0 +1,25 @@
+// test while-if
+int whileIf() {
+  int a;
+  a = 0;
+  int b;
+  b = 0;
+  while (a < 100) {
+    if (a == 5) {
+      b = 25;
+    }
+    else if (a == 10) {
+      b = 42;  
+    }
+    else {
+      b = a * 2;
+    }
+    a = a + 1;
+  }
+  return (b);
+}
+
+
+int main(){
+  return (whileIf());
+}