GH-47483: [C++] Bump vendored xxhash to 0.8.3 (#47476)

### Rationale for this change

We are using an older version, this might fix the current failure for test-conda-cpp-valgrind failures. The upgrade might also come with some improvements / fixes.

### What changes are included in this PR?

Update vendored xxhash to newer version:
- https://github.com/Cyan4973/xxHash/releases/tag/v0.8.3

### Are these changes tested?

Yes, via CI.

### Are there any user-facing changes?

No

* GitHub Issue: #47483

Authored-by: Raúl Cumplido <[email protected]>
Signed-off-by: Antoine Pitrou <[email protected]>

Author: raulcd

cpp/CMakeLists.txt

@@ -351,6 +351,12 @@ endif()
 
 include(SetupCxxFlags)
 
+if(${CMAKE_CXX_FLAGS_DEBUG} MATCHES "-Og")
+  # GH-47475: xxhash fails inlining when -Og is used.
+  # See: https://github.com/Cyan4973/xxHash/issues/943
+  add_definitions(-DXXH_NO_INLINE_HINTS)
+endif()
+
 #
 # Linker flags
 #

cpp/src/arrow/vendored/xxhash/README.md

@@ -17,5 +17,5 @@
   under the License.
 -->
 
-The files in this directory are vendored from xxHash git tag v0.8.2
+The files in this directory are vendored from xxHash git tag v0.8.3
 (https://github.com/Cyan4973/xxHash).

cpp/src/arrow/vendored/xxhash/xxhash.c

@@ -1,6 +1,6 @@
 /*
  * xxHash - Extremely Fast Hash algorithm
- * Copyright (C) 2012-2021 Yann Collet
+ * Copyright (C) 2012-2023 Yann Collet
  *
  * BSD 2-Clause License (https://www.opensource.org/licenses/bsd-license.php)
  *
@@ -32,12 +32,11 @@
  *   - xxHash source repository: https://github.com/Cyan4973/xxHash
  */
 
-
 /*
  * xxhash.c instantiates functions defined in xxhash.h
  */
 
-#define XXH_STATIC_LINKING_ONLY   /* access advanced declarations */
-#define XXH_IMPLEMENTATION   /* access definitions */
+#define XXH_STATIC_LINKING_ONLY /* access advanced declarations */
+#define XXH_IMPLEMENTATION      /* access definitions */
 
 #include "xxhash.h"