[compiler-rt] Fix compiler warnings and runtime errors in sanitizer RT strxfrm(_l) test cases.

[dokyungs]

Summary

Fixed an implicit definition warning by including <string.h>. Also fixed run-time assertions that the return value of strxfrm_l calls is less than the buffer size by increasing the size of the referenced buffer.

[morehouse]

LGTM. Thank you DK!

compiler-rt/test/msan/__strxfrm_l.cpp

 // RUN: %clangxx_msan -std=c++11 -O0 -g %s -o %t && %run %t
 // REQUIRES: x86_64-linux
 
 #include <assert.h>
 #include <locale.h>
 #include <sanitizer/msan_interface.h>
 #include <stdlib.h>
 #include <string.h>
 
 extern "C" decltype(strxfrm_l) __strxfrm_l;
 
 int main(void) {
-  char q[10];
+  char q[100];
   locale_t loc = newlocale(LC_ALL_MASK, "", (locale_t)0);
   size_t n = __strxfrm_l(q, "qwerty", sizeof(q), loc);
   assert(n < sizeof(q));
   __msan_check_mem_is_initialized(q, n + 1);
   return 0;
 }

compiler-rt/test/sanitizer_common/TestCases/Posix/strxfrm.c

 // RUN: %clang -O0 %s -o %t && %run %t
 // UNSUPPORTED: darwin
 
 #include <assert.h>
 #include <locale.h>
-#include <wchar.h>
+#include <string.h>
 
 int main(int argc, char **argv) {
   char q[10];
   size_t n = strxfrm(q, "abcdef", sizeof(q));
   assert(n < sizeof(q));
 
-  char q2[10];
+  char q2[100];
   locale_t loc = newlocale(LC_ALL_MASK, "", (locale_t)0);
-  n = strxfrm_l(q2, L"qwerty", sizeof(q), loc);
+  n = strxfrm_l(q2, "qwerty", sizeof(q2), loc);
   assert(n < sizeof(q2));
 
   freelocale(loc);
   return 0;
 }