Revert "am be741d47: am 2f460fbe: am 73b5cad9: Merge "bionic: Fix wrong kernel_id in pthread descriptor after fork()""

This reverts commit 76d56cf4a94e875a8b621025e2780775247adb6e, reversing
changes made to c59ba4595be25a1213955233fcf9bcd1afe6438e.

Bug: 6157577

libc/bionic/fork.c

@@ -27,7 +27,6 @@
  */
 #include <unistd.h>
 #include "pthread_internal.h"
-#include "bionic_pthread.h"
 #include "cpuacct.h"
 
 extern int  __fork(void);
@@ -49,9 +48,6 @@ int  fork(void)
         __timer_table_start_stop(0);
         __bionic_atfork_run_parent();
     } else {
-        /* Adjusting the kernel id after a fork */
-        (void)__pthread_settid(pthread_self(), gettid());
-
         /*
          * Newly created process must update cpu accounting.
          * Call cpuacct_add passing in our uid, which will take

libc/bionic/pthread.c

@@ -2292,14 +2292,3 @@ pid_t __pthread_gettid(pthread_t thid)
     pthread_internal_t* thread = (pthread_internal_t*)thid;
     return thread->kernel_id;
 }
-
-int __pthread_settid(pthread_t thid, pid_t tid)
-{
-    if (thid == 0)
-        return EINVAL;
-
-    pthread_internal_t* thread = (pthread_internal_t*)thid;
-    thread->kernel_id = tid;
-
-    return 0;
-}

libc/private/bionic_pthread.h

@@ -35,7 +35,6 @@ __BEGIN_DECLS
 
 /* Internal, not an NDK API */
 extern pid_t __pthread_gettid(pthread_t thid);
-extern int __pthread_settid(pthread_t thid, pid_t tid);
 
 __END_DECLS