PR #1846: Fix build on big endian

Imported from GitHub PR #1846

Currently getting the following compilation error:
```
 error: uninitialized 'const kGolden' [-fpermissive]
```
Merge d91fffa into 52190ca

Merging this change closes #1846

COPYBARA_INTEGRATE_REVIEW=#1846 from miladfarca:fix-be d91fffa
PiperOrigin-RevId: 731041395
Change-Id: Ibee7f5b04ec4e3c5e249321128c0ab46179c5b71

Author: miladfarca

absl/hash/internal/low_level_hash_test.cc

@@ -362,7 +362,7 @@ TEST(LowLevelHashTest, VerifyGolden) {
   };
 
 #if defined(ABSL_IS_BIG_ENDIAN)
-  constexpr uint64_t kGolden[kNumGoldenOutputs];
+  constexpr uint64_t kGolden[kNumGoldenOutputs] = {};
   GTEST_SKIP() << "We only maintain golden data for little endian systems.";
 #else
   constexpr uint64_t kGolden[kNumGoldenOutputs] = {