USAN: applying zero offset to null pointer in ivas_jbm_dec.c
### Basic info
- Commit SHA: 472d3527bb3c63b559cf4a7245181cad18524c08
### Bug description
Clang usan sanitizer test in pipeline found an error:
<!--- Copy sanitizer traceback from command line here -->
```
lib_dec/ivas_jbm_dec.c:1042:24: runtime error: applying zero offset to null pointer
SUMMARY: UndefinedBehaviorSanitizer: nullptr-with-offset lib_dec/ivas_jbm_dec.c:1042:24 in
```
<!--- Copy test job URL here -->
Link to test pipeline: https://forge.3gpp.org/rep/ivas-codec-pc/ivas-codec/-/jobs/218864
### Ways to reproduce
Using the [scripts](https://forge.3gpp.org/rep/ivas-codec-pc/ivas-codec/-/wikis/Software-development/pyivastest-howto#how-to-reproduce-tests):
<!--- check correct sanitizer type -->
<!--- add error pattern if needed -->
```
python3 scripts/IvasBuildAndRunChecks.py --checks CLANG3 -m ISM3_b32_dtx_fb_cbr -p /path/to/my/local/ci_linux_ltv_local.json --usan_supp_file scripts/ubsan.supp --oc BINAURAL
```
or directly:
```
make clean
make -j CLANG=3
./IVAS_cod -dtx -ism 3 NULL NULL NULL -max_band fb 32000 48 ltv48_3ISM.wav bit
./IVAS_dec BINAURAL 48 bit out.wav
```
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issue