FROMLIST: android: binder: Add allocator selftest

(from https://patchwork.kernel.org/patch/9928609/)

binder_alloc_selftest tests that alloc_new_buf handles page allocation and
deallocation properly when allocate and free buffers. The test allocates 5
buffers of various sizes to cover all possible page alignment cases, and
frees the buffers using a list of exhaustive freeing order.

Test: boot the device with ANDROID_BINDER_IPC_SELFTEST config option
enabled. Allocator selftest passes.

Bug: 36007193
Change-Id: I2fe396232b7dfe4bbc50bdba99ca0de9be63cc37
Signed-off-by: Sherry Yang <sherryy@android.com>
diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index 954792a..8afa9f8 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -4579,6 +4579,8 @@
 	/*pr_info("binder_ioctl: %d:%d %x %lx\n",
 			proc->pid, current->pid, cmd, arg);*/
 
+	binder_selftest_alloc(&proc->alloc);
+
 	trace_binder_ioctl(cmd, arg);
 
 	ret = wait_event_interruptible(binder_user_error_wait, binder_stop_on_user_error < 2);