record file fuzzer: fix FD double-own

How this bug was not filed earlier is beyond my
imagination.

Fixes: 306847496
Test: binder_recordedTransactionFileFuzz
Change-Id: If1da3ecf31b3310e1542bc519b4b6890298db242
diff --git a/libs/binder/tests/unit_fuzzers/RecordedTransactionFileFuzz.cpp b/libs/binder/tests/unit_fuzzers/RecordedTransactionFileFuzz.cpp
index e494366..f3006cd 100644
--- a/libs/binder/tests/unit_fuzzers/RecordedTransactionFileFuzz.cpp
+++ b/libs/binder/tests/unit_fuzzers/RecordedTransactionFileFuzz.cpp
@@ -35,7 +35,7 @@
     if (transaction.has_value()) {
         intermediateFile = std::tmpfile();
 
-        android::base::unique_fd fdForWriting(fileno(intermediateFile));
+        android::base::unique_fd fdForWriting(dup(fileno(intermediateFile)));
         auto writeStatus ATTRIBUTE_UNUSED = transaction.value().dumpToFile(fdForWriting);
 
         std::fclose(intermediateFile);