[vm] Prevent nested handling of SIGPROF.

TEST=ci
Bug: #52765
Change-Id: I14301d67ad245d3df96624155b383cb5f4c7f981
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/310975
Reviewed-by: Siva Annamalai <asiva@google.com>
Commit-Queue: Ryan Macnak <rmacnak@google.com>
Reviewed-by: Ben Konyi <bkonyi@google.com>

Author: rmacnak-google

runtime/vm/signal_handler_android.cc

@@ -122,6 +122,7 @@ void SignalHandler::Install(SignalAction action) {
   struct sigaction act = {};
   act.sa_sigaction = action;
   sigemptyset(&act.sa_mask);
+  sigaddset(&act.sa_mask, SIGPROF);  // Prevent nested signals.
   act.sa_flags = SA_RESTART | SA_SIGINFO | SA_ONSTACK;
   r = sigaction(SIGPROF, &act, nullptr);
   ASSERT(r == 0);

runtime/vm/signal_handler_linux.cc

@@ -115,6 +115,7 @@ void SignalHandler::Install(SignalAction action) {
   act.sa_handler = nullptr;
   act.sa_sigaction = action;
   sigemptyset(&act.sa_mask);
+  sigaddset(&act.sa_mask, SIGPROF);  // Prevent nested signals.
   act.sa_flags = SA_RESTART | SA_SIGINFO;
   int r = sigaction(SIGPROF, &act, nullptr);
   ASSERT(r == 0);