修改Sscanf用例crash的问题

Change-Id: I3ad8064485ced9689f1d13feb27d63d6d96af9cc

kernel_lite/io_posix/src/IoTestSscanf.cpp

@@ -151,9 +151,10 @@ HWTEST_F(IoTest, testSscanfChar, Function | MediumTest | Level1)
     EXPECT_EQ(ret, 1) << "> sscanf fail, errno = " << errno;
     EXPECT_EQ(c, 'a');
 
-    ret = sscanf("hello", "%5c", &c);
+    char c2[10] = {0};
+    ret = sscanf("helloworld", "%5c", c2);
     EXPECT_EQ(ret, 1) << "> sscanf fail, errno = " << errno;
-    EXPECT_EQ(c, 'h');
+    EXPECT_EQ(c2, "hello");
 
     ret = sscanf("(a) and |b|", "(%c) and |%c%*c|", &c, &c1);
     EXPECT_EQ(ret, 2) << "> sscanf fail, errno = " << errno;
@@ -617,4 +618,4 @@ HWTEST_F(IoTest, testSscanfReturnValue, Function | MediumTest | Level1)
     EXPECT_EQ(ip[1], 11);
     EXPECT_EQ(ip[2], 11);
     EXPECT_EQ(ip[3], 0);
-}
\ No newline at end of file
+}