As per devkitPro/3dstools@47bea18

Threads: Check the process' resource limit for the max allowed priority when creating a thread and remove the priority clamping code.

Thread: Added priority range checking to svcSetThreadPriority and removed priority clamping code from Thread::SetPriority.

Closes #2400

Kernel: Don't attempt to yield execution in SleepThread(0) if there are no available threads to run.

With this we avoid an useless temporary deschedule of the current thread.

After hwtesting and reverse engineering the kernel, it was found that the CTROS scheduler performs no priority boosting for threads like this, although some other forms of scheduling priority-starved threads might take place.

For example, it was found that hardware interrupts might cause low-priority threads to run if the CPU is preempted in the middle of an SVC handler that deschedules the current (high priority) thread before scheduling it again.

Closes #1904

The regression was caused by a missing check in #2260.

The new behavior is consistent with the real kernel.

This fixes a potential bug where threads would not get removed from said list if they awoke after waiting with WaitSynchronizationN with wait_all = false

Kernel: Remove Thread::wait_objects_index and use wait_objects to hold all the objects that a thread is waiting on.

Kernel: Use different thread statuses when a thread calls WaitSynchronization1 and  WaitSynchronizationN with wait_all = true.

This commit removes the overly general THREADSTATUS_WAIT_SYNCH and replaces it with two more granular statuses:

THREADSTATUS_WAIT_SYNCH_ANY when a thread waits on objects via WaitSynchronization1 or WaitSynchronizationN with wait_all = false.

THREADSTATUS_WAIT_SYNCH_ALL when a thread waits on objects via WaitSynchronizationN with wait_all = true.

Kernel/Mutex: Propagate thread priority changes to other threads inheriting the priority via mutexes

The implementation is based on reverse engineering of the 3DS's kernel.

A mutex holder's priority will be temporarily boosted to the best priority among any threads that want to acquire any of its held mutexes.
When the holder releases the mutex, it's priority will be boosted to the best priority among the threads that want to acquire any of its remaining held mutexes.

This will be useful when implementing mutex priority inheritance.

Not all syscalls should cause reschedules, this commit attempts to remedy that, however, it still does not cover all cases.

Fix Fatal Error in Mini-Mario & Friends - amiibo Challenge