Enable agent attaching during live phase

This is the ART part, the plumbing from VMDebug_attachAgent() to
actually loading the agent into the runtime.

Test: m test-art-host

Bug: 31682382

Change-Id: I3ccc67aa050c1f78278882128983686ed44ddec2
diff --git a/runtime/common_throws.cc b/runtime/common_throws.cc
index b0aba59..0251776 100644
--- a/runtime/common_throws.cc
+++ b/runtime/common_throws.cc
@@ -686,6 +686,15 @@
   va_end(args);
 }
 
+// SecurityException
+
+void ThrowSecurityException(const char* fmt, ...) {
+  va_list args;
+  va_start(args, fmt);
+  ThrowException("Ljava/lang/SecurityException;", nullptr, fmt, &args);
+  va_end(args);
+}
+
 // Stack overflow.
 
 void ThrowStackOverflowError(Thread* self) {