Pass the Java app context information using two separate arrays

Pass the Java app context information using two separate arrays

Instead of using one array with length limits for strings, we can
pass two separate arrays: the first will continue to contain fixed-
size entries, but instead of 256 bytes for strings, we will use
4-byte offsets to a second array, which will contain only those
variable-length strings.

The advantage is that we pass less bytes overall, and we don't
limit the context names or values to 256 bytes anymore.

Signed-off-by: Alexandre Montplaisir <alexmonthy@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>