Implement JVMTI can_signal_thread capability.

Implements the JVMTI can_signal_thread capability and all associated
methods and behaviors. This includes both the StopThread and
InterruptThread functions.

This CL contains the tests for the previous CL.

Test: ./test.py --host -j50
Test: stress --cpu 59 && while ./test/run-test --host 1934; do; done

Bug: 62821960
Bug: 34415266
Change-Id: I7b6fc37da0d2673caa993e486f078cf129d74c0f
diff --git a/test/Android.bp b/test/Android.bp
index d2eccb0..6b5a739 100644
--- a/test/Android.bp
+++ b/test/Android.bp
@@ -227,6 +227,7 @@
         "ti-agent/redefinition_helper.cc",
         "ti-agent/suspension_helper.cc",
         "ti-agent/stack_trace_helper.cc",
+        "ti-agent/threads_helper.cc",
         "ti-agent/trace_helper.cc",
         "ti-agent/exceptions_helper.cc",
         // This is the list of non-special OnLoad things and excludes BCI and anything that depends
@@ -276,6 +277,7 @@
         "1927-exception-event/exception_event.cc",
         "1930-monitor-info/monitor.cc",
         "1932-monitor-events-misc/monitor_misc.cc",
+        "1934-jvmti-signal-thread/signal_threads.cc",
     ],
     shared_libs: [
         "libbase",