tp: fix memory leak of table objects

This CL adds the missing virtual destructor which was cauisng memory
leaks as dynamic tables which were upcast to Table would not be
correctly destroyed when the SQLite cursor was destroyed.

Change-Id: I56bc3d0b078267393b71450a1b644847a39c0a0b
diff --git a/BUILD b/BUILD
index fcb16ab..042d95a 100644
--- a/BUILD
+++ b/BUILD
@@ -813,6 +813,7 @@
         "src/trace_processor/tables/metadata_tables.h",
         "src/trace_processor/tables/profiler_tables.h",
         "src/trace_processor/tables/slice_tables.h",
+        "src/trace_processor/tables/table_destructors.cc",
         "src/trace_processor/tables/track_tables.h",
     ],
 )