Change-Id: I43dfbabcbe686c31cb54e6b95688af1fa35a3d24

Change-Id: I57d57881ef5c158d41be1bf1e3714332d50cd3a9

Earlier, the consume method of RtpH263Reader was changing the bytes of the
input bitstream during header parse. This commit copies the input into
local context and changes the local variable as per the specifications
thus keeping the input constant.

This reverts commit 3bacb16.

This change is done to keep the frame data unchanged.
RtpH263Reader changes the header data in input, so to send the same
RTP packet across multiple tests, each test copies the frame data
into a new packet and sends that to the reader.