Allow __NR_pipe for 32-bit processes

Used by 32-bit debuggers

Bug: 34716063
Test: Make sure a Chrome crash produces a valid stack trace in logcat
Change-Id: Ie42f035da7f19ace403eb2111524f02c0bbfd0d5

init/seccomp.cpp

@@ -213,6 +213,9 @@ bool set_seccomp_filter() {
     // Needed for kernel to restart syscalls
     AllowSyscall(f, 0);  // __NR_restart_syscall
 
+    // Needed for debugging 32-bit Chrome
+    AllowSyscall(f, 42); // __NR_pipe
+
     // arm32-on-arm64 only filter - autogenerated from bionic syscall usage
     for (size_t i = 0; i < arm_filter_size; ++i)
         f.push_back(arm_filter[i]);