Add IRExecutionUnitSP to lldb-forward and use it instead of hand-rolling in place.

llvm-svn: 252129
diff --git a/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionParser.h b/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionParser.h
index 96c4315..3c05538 100644
--- a/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionParser.h
+++ b/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionParser.h
@@ -113,7 +113,7 @@
     Error
     PrepareForExecution (lldb::addr_t &func_addr,
                          lldb::addr_t &func_end,
-                         std::shared_ptr<IRExecutionUnit> &execution_unit_sp,
+                         lldb::IRExecutionUnitSP &execution_unit_sp,
                          ExecutionContext &exe_ctx,
                          bool &can_interpret,
                          lldb_private::ExecutionPolicy execution_policy) override;