Allow SYS_sched_getparam and SYS_sched_getscheduler
musl uses them for pthread_getschedparam()

source: https://git.alpinelinux.org/aports/commit/community/chromium?id=54af9f8ac24f52d382c5758e2445bf0206eff40e

--- a/src/3rdparty/chromium/services/service_manager/sandbox/linux/bpf_renderer_policy_linux.cc	2020-09-01 13:02:34.000000000 +0200
+++ -	2020-09-10 19:16:13.884275822 +0200
@@ -88,11 +88,18 @@
     case __NR_sysinfo:
     case __NR_times:
     case __NR_uname:
+#if !defined(__GLIBC__)
+    case __NR_sched_getparam:
+    case __NR_sched_getscheduler:
+    case __NR_sched_setscheduler:
+#endif
       return Allow();
     case __NR_sched_getaffinity:
+#if defined(__GLIBC__)
     case __NR_sched_getparam:
     case __NR_sched_getscheduler:
     case __NR_sched_setscheduler:
+#endif
       return sandbox::RestrictSchedTarget(GetPolicyPid(), sysno);
     case __NR_prlimit64:
       // See crbug.com/662450 and setrlimit comment above.