Add ftruncate64 to audio sandbox policy.

Audio sandbox policy currently allows ftruncate syscall; adding ftruncate64
used on x86 systems.

This fix solves browser_tests failures on 32 bit Linux bots. With ftruncate64
blocked, IPC between audio process and renderer was failing leading to audio
render errors.

Bug: 890850
Cq-Include-Trybots: luci.chromium.try:android_optional_gpu_tests_rel;luci.chromium.try:linux_optional_gpu_tests_rel;luci.chromium.try:mac_optional_gpu_tests_rel;luci.chromium.try:win_optional_gpu_tests_rel
Change-Id: I6b09429c018468e0eb037498514df048fe79d520
Reviewed-on: https://chromium-review.googlesource.com/c/1282407
Commit-Queue: Marina Ciocea <[email protected]>
Reviewed-by: Robert Sesek <[email protected]>
Cr-Commit-Position: refs/heads/master@{#600555}

services/service_manager/sandbox/linux/bpf_audio_policy_linux.cc

@@ -36,6 +36,9 @@ ResultExpr AudioProcessPolicy::EvaluateSyscall(int system_call_number) const {
 #if defined(__NR_ftruncate)
     case __NR_ftruncate:
 #endif
+#if defined(__NR_ftruncate64)
+    case __NR_ftruncate64:
+#endif
 #if defined(__NR_getdents)
     case __NR_getdents:
 #endif