Fix WasmEHFuncInfo.h to include what it uses

This fixes clang+llvm build with Modules and local submodule visibility.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@335181 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/CodeGen/WasmEHFuncInfo.h

@@ -14,6 +14,11 @@
 #ifndef LLVM_CODEGEN_WASMEHFUNCINFO_H
 #define LLVM_CODEGEN_WASMEHFUNCINFO_H
 
+#include "llvm/ADT/PointerUnion.h"
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/CodeGen/MachineBasicBlock.h"
+#include "llvm/IR/BasicBlock.h"
+
 namespace llvm {
 
 using BBOrMBB = PointerUnion<const BasicBlock *, MachineBasicBlock *>;