Crash with rate switching under MDCT_STEREO_PLC_FADE_2_BG_NOISE

Basic info

• Commit SHA: 64399db4
• Platform: all

Bug description

Under switch MDCT_STEREO_PLC_FADE_2_BG_NOISE, the decoder can crash for rate switching scenarios with DTX since a PLC-related structure can be un-allocated.

Ways to reproduce

Bitstream file is attached, already contains frame errors as used in sanitizer pipeline. test_stereo_stereo_b13_128_dtx_swb_rs_fer_ep_015_g192.192

git checkout 64399db46f7a237cd21163cfa53137f9f18cf989
make clean
make -j

./IVAS_dec stereo 32 test_stereo_stereo_b13_128_dtx_swb_rs_fer_ep_015_g192.192 out.wav