EGPRS: add test case to show EPDAN BSN out of window bug

This patch adds a test case test_tbf_epdan_out_of_rx_window,
which expects a current bug with EPDAN for interpretation of the
bitmap explained in section 9.1.8.2.4 in 44.060 version 7.27.0
Release 7. The specification explains that a bit within the
uncompressed bitmap whose corresponding BSN is not within the
transmit window shall be ignored. But current PCU implementation
drops the EPDAN and does not update status of the BSN which are
inside the window. The test's expectation is corrected along with
the bug fix in a subsequent commit.

Related: OS#1789

Change-Id: If32b67f5c05707155281128b776a90a1e3d587b2
3 files changed