macOS Sandbox: Add syscalls related to synchronization

These sycalls are used in libpthread.
https://opensource.apple.com/source/libpthread/libpthread-416.40.3/src/internal.h.auto.html

Bug: 1050158
Change-Id: I41537612736122d6a7a9c1c129ecfc13ef01b419
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2149476Reviewed-by: Greg Kerr <kerrnel@chromium.org>
Commit-Queue: Tsuyoshi Horo <horo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#759098}

services/service_manager/sandbox/mac/common.sb

@@ -271,7 +271,14 @@
       (syscall-number SYS_proc_info)
       (syscall-number SYS_psynch_mutexdrop)
       (syscall-number SYS_psynch_mutexwait)
+      (syscall-number SYS_psynch_rw_downgrade)
+      (syscall-number SYS_psynch_rw_longrdlock)
       (syscall-number SYS_psynch_rw_rdlock)
+      (syscall-number SYS_psynch_rw_unlock)
+      (syscall-number SYS_psynch_rw_unlock2)
+      (syscall-number SYS_psynch_rw_upgrade)
+      (syscall-number SYS_psynch_rw_wrlock)
+      (syscall-number SYS_psynch_rw_yieldwrlock)
       (syscall-number SYS_read)
       (syscall-number SYS_read_nocancel)
       (syscall-number SYS_readlink)