tests: kernel.scheduler.multiq: test_k_thread_suspend_init_null failure

[erwango]

Describe the bug
Following issue appears when running tests/kernel/sched/schedule_api on disco_l475_iot1 or frdm_k64f

START - test_k_thread_suspend_init_null                                         
E: (nil) is not a valid k_thread                                                
E: address is not a known kernel object                                         
E: syscall z_vrfy_k_thread_suspend failed check: access denied                  
E: r0/a1:  0x00000000  r1/a2:  0x00000000  r2/a3:  0x00000000                   
E: r3/a4:  0x00000000 r12/ip:  0x00000000 r14/lr:  0x00000000                   
E:  xpsr:  0x00000000                                                           
E: Faulting instruction address (r15/pc): 0x86cbe968                            
E: >>> ZEPHYR FATAL ERROR 3: Kernel oops on CPU 0                               
E: Current thread: 0x20001830 (unknown)                                         
Caught system error -- reason 3 1                                               
Fatal error expected as part of test case.                                      
 PASS - test_k_thread_suspend_init_null in 0.45 seconds                         
=================================================================== 

To Reproduce
twister -p disco_l475_iot1 -T kernel/sched/schedule_api --device-testing --device-serial /dev/ttyACM0

Expected behavior
Test should be passed

Logs and console output

START - test_k_thread_suspend_init_null                                         
E: (nil) is not a valid k_thread                                                
E: address is not a known kernel object                                         
E: syscall z_vrfy_k_thread_suspend failed check: access denied                  
E: r0/a1:  0x00000000  r1/a2:  0x00000000  r2/a3:  0x00000000                   
E: r3/a4:  0x00000000 r12/ip:  0x00000000 r14/lr:  0x00000000                   
E:  xpsr:  0x00000000                                                           
E: Faulting instruction address (r15/pc): 0x86cbe968                            
E: >>> ZEPHYR FATAL ERROR 3: Kernel oops on CPU 0                               
E: Current thread: 0x20001830 (unknown)                                         
Caught system error -- reason 3 1                                               
Fatal error expected as part of test case.                                      
 PASS - test_k_thread_suspend_init_null in 0.45 seconds                         
=================================================================== 

Environment (please complete the following information):

• OS: (e.g. Linux, MacOS, Windows): Ubuntu
• Toolchain (e.g Zephyr SDK, ...): zephyr-sdk-0.12.2
• Commit SHA or Version used: v2.6.0-rc2

Additional context
Add any other context about the problem here.