demux/playlist/qtl: segfault during root-node searching
With the attached sample:
ERROR: AddressSanitizer: SEGV on unknown address 0x000000000008 (pc 0x7f5e744afd36 bp 0x7f5e56adb000 sp 0x7f5e56adaa88 T5)
[#0](https://code.videolan.org/videolan/vlc/-/issues/0) 0x7f5e744afd35 in __GI_strlen (/usr/lib/libc.so.6+0x81d35)
[#1](https://code.videolan.org/videolan/vlc/-/issues/1) 0x7f5e744787f9 in _IO_vfprintf_internal (/usr/lib/libc.so.6+0x4a7f9)
[#2](https://code.videolan.org/videolan/vlc/-/issues/2) 0x7f5e74479705 in buffered_vfprintf (/usr/lib/libc.so.6+0x4b705)
[#3](https://code.videolan.org/videolan/vlc/-/issues/3) 0x7f5e74476a25 in _IO_vfprintf_internal (/usr/lib/libc.so.6+0x48a25)
[#4](https://code.videolan.org/videolan/vlc/-/issues/4) 0x7f5e74529075 in __GI___vfprintf_chk (/usr/lib/libc.so.6+0xfb075)
[#5](https://code.videolan.org/videolan/vlc/-/issues/5) 0x7f5e7008d1db in vfprintf /usr/include/bits/stdio2.h:127:10
[#6](https://code.videolan.org/videolan/vlc/-/issues/6) 0x7f5e7008d1db in LogConsoleColor /home/refp/work/videolan/vlc/git/modules/logger/console.c:62
[#7](https://code.videolan.org/videolan/vlc/-/issues/7) 0x7f5e75b8210f in vlc_vaLogCallback /home/refp/work/videolan/vlc/git/src/misc/messages.c:65:5
[#8](https://code.videolan.org/videolan/vlc/-/issues/8) 0x7f5e75b81f7a in vlc_vaLog /home/refp/work/videolan/vlc/git/src/misc/messages.c:140:9
[#9](https://code.videolan.org/videolan/vlc/-/issues/9) 0x7f5e75b82290 in vlc_Log /home/refp/work/videolan/vlc/git/src/misc/messages.c:161:5
[#10](https://code.videolan.org/videolan/vlc/-/issues/10) 0x7f5e6aacadbc in Demux /home/refp/work/videolan/vlc/git/modules/demux/playlist/qtl.c:129:9
[#11](https://code.videolan.org/videolan/vlc/-/issues/11) 0x7f5e75afd218 in MainLoopDemux /home/refp/work/videolan/vlc/git/src/input/input.c:559:17
[#12](https://code.videolan.org/videolan/vlc/-/issues/12) 0x7f5e75afa1f6 in MainLoop /home/refp/work/videolan/vlc/git/src/input/input.c:705:17
[#13](https://code.videolan.org/videolan/vlc/-/issues/13) 0x7f5e75afb402 in Run /home/refp/work/videolan/vlc/git/src/input/input.c:495:9
[#14](https://code.videolan.org/videolan/vlc/-/issues/14) 0x7f5e74bf82e6 in start_thread (/usr/lib/libpthread.so.0+0x72e6)
[#15](https://code.videolan.org/videolan/vlc/-/issues/15) 0x7f5e7451a54e in __GI___clone (/usr/lib/libc.so.6+0xec54e)