Fix wrong offset in large logs when some are skipped.

Timestamps in large logs written to console have wrong
positive offset when logs are partly skipped. So you never
see the last timestamp in the situation.

Changes made in commit 5a5e7b9 touch Parse From Finish logic
and began the offset.
They were partly reverted.

src/main/java/hudson/plugins/timestamper/annotator/ConsoleLogParser.java

@@ -105,7 +105,6 @@ private ConsoleLogParser.Result parseFromStart(InputStream inputStream, long pos
 
   private ConsoleLogParser.Result parseFromFinish(InputStream inputStream) throws IOException {
     ConsoleLogParser.Result result = new ConsoleLogParser.Result();
-    result.lineNumber = -1;
 
     int value = inputStream.read();
     result.atNewLine = isNewLine(value);

src/test/java/hudson/plugins/timestamper/annotator/ConsoleLogParserTest.java

@@ -150,7 +150,7 @@ public void testSeekWithinLineNegative_isBuilding() throws Exception {
   public void testSeekWithinLineNegative_notBuilding() throws Exception {
     assumeThat(isBuilding, is(false));
     ConsoleLogParser.Result result = new ConsoleLogParser.Result();
-    result.lineNumber = -5;
+    result.lineNumber = -4;
     assertThat(seek(1 - logLength), is(result));
   }
 
@@ -167,7 +167,7 @@ public void testSeekNextLineNegative_isBuilding() throws Exception {
   public void testSeekNextLineNegative_notBuilding() throws Exception {
     assumeThat(isBuilding, is(false));
     ConsoleLogParser.Result result = new ConsoleLogParser.Result();
-    result.lineNumber = -4;
+    result.lineNumber = -3;
     result.atNewLine = true;
     assertThat(seek(2 - logLength), is(result));
   }