1ISM 2 EXT decoder crashes for 48kbps DTX

Basic info

• Commit SHA: main, tested at 34c6b03f
• Platform: Linux

Bug description

There is a segfault in the ISM1 decoder when using the new longer testvector related to HQ core.

Ways to reproduce

Get longer testvectors from the testfile repo:

git clone git@forge.3gpp.org:ivas-codec-pc/ivas-pc-testfiles.git

Then

IVAS_cod -ism 1 NULL -dtx -max_band fb 48000 48 ivas-pc-tetfiles/ltv48_1ISM.wav bs.192
IVAS_dec EXT 48 bs.192 out.wav

results in a segfault. Running with msan gives:

MemorySanitizer:DEADLYSIGNAL
==2975862==ERROR: MemorySanitizer: SEGV on unknown address 0x000000000000 (pc 0x000000eddc39 bp 0x7ffcd69e8bc0 sp 0x7ffcd69e87a0 T2975862)
==2975862==The signal is caused by a READ memory access.
==2975862==Hint: address points to the zero page.
    #0 0xeddc38 in apply_noisefill_HQ /local/knj/ivas-codec/lib_com/hq_tools.c
    #1 0xe89a87 in fill_spectrum /local/knj/ivas-codec/lib_com/fill_spectrum.c:181:9

MemorySanitizer can not provide additional info.
SUMMARY: MemorySanitizer: SEGV /local/knj/ivas-codec/lib_com/hq_tools.c in apply_noisefill_HQ
==2975862==ABORTING