Fix int conversion warning on Windows

Change-Id: I48147645784402e7cf004a82151d66f337d1664e

cpp/src/arrow/array/builder_binary.cc

@@ -69,7 +69,7 @@ Status BinaryBuilder::ReserveData(int64_t elements) {
   return Status::OK();
 }
 
-Status BinaryBuilder::AppendOverflow(int32_t num_bytes) {
+Status BinaryBuilder::AppendOverflow(int64_t num_bytes) {
   std::stringstream ss;
   ss << "BinaryArray cannot contain more than " << kBinaryMemoryLimit << " bytes, have "
      << num_bytes;

cpp/src/arrow/array/builder_binary.h

@@ -121,7 +121,7 @@ class ARROW_EXPORT BinaryBuilder : public ArrayBuilder {
   TypedBufferBuilder<int32_t> offsets_builder_;
   TypedBufferBuilder<uint8_t> value_data_builder_;
 
-  Status AppendOverflow(int32_t num_bytes);
+  Status AppendOverflow(int64_t num_bytes);
 
   Status AppendNextOffset() {
     const int64_t num_bytes = value_data_builder_.length();