Update DecimalUtils.java

seconds value already has the correct sign, so remove the sign from the nanos part

datetime/src/main/java/com/fasterxml/jackson/datatype/jsr310/DecimalUtils.java

@@ -17,6 +17,7 @@
 package com.fasterxml.jackson.datatype.jsr310;
 
 import java.math.BigDecimal;
+import java.time.Instant;
 import java.util.function.BiFunction;
 
 /**
@@ -136,6 +137,11 @@ else if (seconds.scale() < -63) {
             // Now we know that seconds has reasonable scale, we can safely chop it apart.
             secondsOnly = seconds.longValue();
             nanosOnly = nanoseconds.subtract(new BigDecimal(secondsOnly).scaleByPowerOfTen(9)).intValue();
+
+
+            if (secondsOnly < 0 && secondsOnly > Instant.MIN.getEpochSecond()) {
+                nanosOnly = Math.abs(nanosOnly);
+            }
         }
 
         return convert.apply(secondsOnly, nanosOnly);