fixes tohost behavior of SC wrapper and cycle-estimate plugin

src/iss/plugin/cycle_estimate.h

@@ -48,10 +48,10 @@ namespace plugin {
 
 class cycle_estimate: public vm_plugin {
     struct instr_desc {
-        size_t size;
-        bool is_branch;
-        unsigned not_taken;
-        unsigned taken;
+        size_t size{0};
+        bool is_branch{false};
+        unsigned not_taken{1};
+        unsigned taken{1};
         std::function<unsigned(uint64_t)> f;
     };
 
@@ -79,6 +79,7 @@ public:
 private:
     iss::instrumentation_if *instr_if{nullptr};
     uint32_t* reg_base_ptr {nullptr};
+    instr_desc illegal_desc{};
     std::vector<instr_desc> delays;
     unsigned current_delay{0};
     struct pair_hash {