Set legacyTimestamp to false by default

Author: imjalpreet

presto-main-base/src/main/java/com/facebook/presto/sql/analyzer/FunctionsConfig.java

@@ -41,7 +41,7 @@ public class FunctionsConfig
     private ArrayAggGroupImplementation arrayAggGroupImplementation = ArrayAggGroupImplementation.NEW;
     private MultimapAggGroupImplementation multimapAggGroupImplementation = MultimapAggGroupImplementation.NEW;
     private boolean legacyRowFieldOrdinalAccess;
-    private boolean legacyTimestamp = true;
+    private boolean legacyTimestamp;
     private boolean parseDecimalLiteralsAsDouble;
     private boolean fieldNamesInJsonCastEnabled;
     private boolean warnOnPossibleNans;