[Java] Remove the need for blockLength field in group encoders.

Author: mjpt777

sbe-tool/src/main/java/uk/co/real_logic/sbe/generation/java/JavaGenerator.java

@@ -460,7 +460,6 @@ private void generateGroupEncoderClassHeader(
  indent + " dimensions.numInGroup((%7$s)count);\n" +
  indent + " index = -1;\n" +
  indent + " this.count = count;\n" +
- indent + " blockLength = %6$d;\n" +
  indent + " parentMessage.limit(parentMessage.limit() + HEADER_SIZE);\n" +
  indent + " }\n\n",
  parentMessageClassName,
@@ -491,7 +490,7 @@ private void generateGroupEncoderClassHeader(
  indent + " throw new java.util.NoSuchElementException();\n" +
  indent + " }\n\n" +
  indent + " offset = parentMessage.limit();\n" +
- indent + " parentMessage.limit(offset + blockLength);\n" +
+ indent + " parentMessage.limit(offset + sbeBlockLength());\n" +
  indent + " ++index;\n\n" +
  indent + " return this;\n" +
  indent + " }\n",
@@ -548,7 +547,6 @@ private void generateGroupEncoderClassDeclaration(
  indent + " private final %3$s dimensions = new %3$s();\n" +
  indent + " private %4$s parentMessage;\n" +
  indent + " private %5$s buffer;\n" +
- indent + " private int blockLength;\n" +
  indent + " private int count;\n" +
  indent + " private int index;\n" +
  indent + " private int offset;\n\n",