Fix SIGSEGV when table_properties is nullptr

Summary: out.table_properties is allowed to be nullptr if the compaction failed with a non-OK status. Because of how the code is structured, `CompactionJob::RetrieveResultsAndCleanup()` is called even if the compaction failed (it doesn't care about the results, but it cares about the cleanup).

Test Plan: Compiles

Reviewers: #sys-eng_team

Differential Revision: https://rockset.phacility.com/D10613

Author: igorcanadi

db/compaction/compaction_job.cc

@@ -1887,7 +1887,9 @@ void CompactionJob::RetrieveResultsAndCleanup(
 
       OutputFile file;
       file.pathname = path;
-      file.table_properties = *(out.table_properties);
+      if (out.table_properties) {
+        file.table_properties = *(out.table_properties);
+      }
       file.file_size = out.meta.fd.file_size;
       file.num_entries = out.meta.num_entries;
       file.num_deletions = out.meta.num_deletions;