Fix rot13 test on big-endian platforms (#2386)

Author: SoniEx2

src/test-interp.cc

@@ -505,8 +505,13 @@ TEST_F(InterpTest, Rot13) {
 
     EXPECT_LT(ptr + size, memory->ByteSize());
 
+#if WABT_BIG_ENDIAN
+    std::copy(string_data.rbegin(), string_data.rbegin() + size,
+              memory->UnsafeData() + memory->ByteSize() - ptr - size);
+#else
     std::copy(string_data.begin(), string_data.begin() + size,
               memory->UnsafeData() + ptr);
+#endif
 
     results[0].Set(size);
     return Result::Ok;
@@ -527,8 +532,14 @@ TEST_F(InterpTest, Rot13) {
     EXPECT_LT(ptr + size, memory->ByteSize());
 
     string_data.resize(size);
+#if WABT_BIG_ENDIAN
+    std::copy(memory->UnsafeData() + memory->ByteSize() - ptr - size,
+              memory->UnsafeData() + memory->ByteSize() - ptr,
+              string_data.rbegin());
+#else
     std::copy(memory->UnsafeData() + ptr, memory->UnsafeData() + ptr + size,
               string_data.begin());
+#endif
 
     return Result::Ok;
   };