[libc++][test] Fix missing include in `bit_ceil.fail.cpp`

The test uses `size_t` but does not include a header defining it.  Include
`<cstddef>` which provides `size_t`.

Differential Revision: https://reviews.llvm.org/D141284

diff --git a/libcxx/test/std/numerics/bit/bit.pow.two/bit_ceil.fail.cpp b/libcxx/test/std/numerics/bit/bit.pow.two/bit_ceil.fail.cpp
index 4c4c901..962291d 100644 (file)
--- a/libcxx/test/std/numerics/bit/bit.pow.two/bit_ceil.fail.cpp
+++ b/libcxx/test/std/numerics/bit/bit.pow.two/bit_ceil.fail.cpp
@@ -15,9 +15,10 @@
 //          T is an unsigned integer type
 
 #include <bit>
+#include <cassert>
+#include <cstddef>
 #include <cstdint>
 #include <limits>
-#include <cassert>
 
 #include "test_macros.h"