Mark Thread As Stopped

#   ROUTINE: Mark Thread As Stopped
#       Mark the specified thread as not in use.
#       Parameters:
#           r4 = (threadIndex) Specified thread index

8014c940: 3c028016 lui r2,0x8016
8014c944: 8c425f98 lw r2,0x5f98(r2)                     #   threads
8014c948: 00042280 sll r4,r4,0x0a                       #   threadIndex * sizeof(thread)
8014c94c: 00822021 addu r4,r4,r2                        #   threads[threadIndex]
8014c950: 03e00008 jr r31
8014c954: ac800048 sw r0,0x0048(r4)                     #   threads[threadIndex].isRunning = false