[SpeculativeJIT] Add missing include

Fix examples after 0faa181.

Author: nikic

llvm/examples/SpeculativeJIT/SpeculativeJIT.cpp

@@ -7,6 +7,7 @@
 #include "llvm/ExecutionEngine/Orc/IndirectionUtils.h"
 #include "llvm/ExecutionEngine/Orc/JITTargetMachineBuilder.h"
 #include "llvm/ExecutionEngine/Orc/RTDyldObjectLinkingLayer.h"
+#include "llvm/ExecutionEngine/Orc/SelfExecutorProcessControl.h"
 #include "llvm/ExecutionEngine/Orc/SpeculateAnalyses.h"
 #include "llvm/ExecutionEngine/Orc/Speculation.h"
 #include "llvm/ExecutionEngine/Orc/TargetProcess/TargetExecutionUtils.h"