Use std::to_string instead of std::stringstream.

Bug: N/A
Test: ran tests
Change-Id: Ifeb7cf9517bcc05459e7ce316eb7604042510935
diff --git a/tests/stdlib_test.cpp b/tests/stdlib_test.cpp
index e429de6..93877f3 100644
--- a/tests/stdlib_test.cpp
+++ b/tests/stdlib_test.cpp
@@ -33,7 +33,7 @@
 #include <sys/wait.h>
 
 #include <limits>
-#include <sstream>
+#include <string>
 
 // The random number generator tests all set the seed, get four values, reset the seed and check
 // that they get the first two values repeated, and then reset the seed and check two more values
@@ -678,7 +678,7 @@
 
   if (std::numeric_limits<T>::is_signed) {
     // Minimum (such as -128).
-    std::string min{(std::stringstream{} << std::numeric_limits<T>::min()).str()};
+    std::string min{std::to_string(std::numeric_limits<T>::min())};
     ASSERT_EQ(std::numeric_limits<T>::min(), fn(min.c_str(), &end_p, 0));
     // Too negative (such as -129).
     min.back() = (min.back() + 1);
@@ -688,7 +688,7 @@
   }
 
   // Maximum (such as 127).
-  std::string max{(std::stringstream{} << std::numeric_limits<T>::max()).str()};
+  std::string max{std::to_string(std::numeric_limits<T>::max())};
   ASSERT_EQ(std::numeric_limits<T>::max(), fn(max.c_str(), &end_p, 0));
   // Too positive (such as 128).
   max.back() = (max.back() + 1);