GH-50149: [C++][Parquet] Avoid process abort when encoding fuzzer encounters OOM (#50150)

### Rationale for this change

In the Parquet encoding fuzzer, an OOM error when trying to roundtrip the encoding payload leads to a hard error that is reported as an issue on OSS-Fuzz. This should be converted to a soft error, i.e. a potential log message but not a process abort.

### Are these changes tested?

By additional fuzz regression file as well as manually.

### Are there any user-facing changes?

No.

* GitHub Issue: #50149

Authored-by: Antoine Pitrou <antoine@python.org>
Signed-off-by: Antoine Pitrou <antoine@python.org>

Author: pitrou

cpp/src/parquet/arrow/fuzz_encoding_internal.cc

@@ -290,23 +290,24 @@ struct TypedFuzzEncoding {
     }
 
     // Re-encode and re-decode using roundtrip encoding
-    {
-      auto compare_chunk = [&](int offset, std::span<const c_type> chunk_values) {
-        return CompareChunkAgainstReference(offset, chunk_values);
-      };
+    auto compare_chunk = [&](int offset, std::span<const c_type> chunk_values) {
+      return CompareChunkAgainstReference(offset, chunk_values);
+    };
+    auto do_roundtrip = [&]() -> Status {
       auto encoder = MakeEncoder(roundtrip_encoding_);
       BEGIN_PARQUET_CATCH_EXCEPTIONS
       if constexpr (arrow_supported()) {
         encoder->Put(*reference_array_);
         auto reencoded_buffer = encoder->FlushValues();
         auto reencoded_data = reencoded_buffer->template span_as<uint8_t>();
-        auto array = DecodeArrow(roundtrip_encoding_, reencoded_data).ValueOrDie();
-        ARROW_CHECK_OK(array->ValidateFull());
-        ARROW_CHECK_OK(CompareAgainstReference(array));
+        ARROW_ASSIGN_OR_RAISE(auto array,
+                              DecodeArrow(roundtrip_encoding_, reencoded_data));
+        RETURN_NOT_OK(array->ValidateFull());
+        RETURN_NOT_OK(CompareAgainstReference(array));
         // Compare with reading raw values
         for (const int chunk_size : chunk_sizes()) {
-          ARROW_CHECK_OK(RunOnDecodedChunks(roundtrip_encoding_, reencoded_data,
-                                            chunk_size, compare_chunk));
+          RETURN_NOT_OK(RunOnDecodedChunks(roundtrip_encoding_, reencoded_data,
+                                           chunk_size, compare_chunk));
         }
       } else {
         encoder->Put(reference_values_.data(),
@@ -315,14 +316,19 @@ struct TypedFuzzEncoding {
         auto reencoded_data = reencoded_buffer->template span_as<uint8_t>();
         // Vary chunk sizes
         for (const int chunk_size : chunk_sizes()) {
-          ARROW_CHECK_OK(RunOnDecodedChunks(roundtrip_encoding_, reencoded_data,
-                                            chunk_size, compare_chunk));
+          RETURN_NOT_OK(RunOnDecodedChunks(roundtrip_encoding_, reencoded_data,
+                                           chunk_size, compare_chunk));
         }
       }
       END_PARQUET_CATCH_EXCEPTIONS
+      return Status::OK();
+    };
+    Status roundtrip_status = do_roundtrip();
+    // OOM when attempting to roundtrip is not a hard failure, any other error is.
+    if (!roundtrip_status.IsOutOfMemory()) {
+      ARROW_CHECK_OK(roundtrip_status);
     }
-
-    return Status::OK();
+    return roundtrip_status;
   }
 
  protected: