[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/66_exgcd.sy

@@ -0,0 +1,22 @@
+int exgcd(int a,int b,int x[],int y[]) {
+	if(b == 0) {
+		x[0] = 1;
+		y[0] = 0; 
+		return a;			
+	}
+	else {
+		int r = exgcd(b, a % b, x, y);		
+		int t = x[0];
+		x[0] = y[0];
+		y[0] = (t - a / b * y[0]);
+		return r;
+	}
+} 
+
+int main() {
+	int a = 7, b = 15, x[1] = {1}, y[1] = {1};
+	exgcd(a, b, x, y);
+	x[0] = (x[0] % b + b) % b;
+	putint(x[0]);
+	return 0;
+}