[WASM] Implements catch for the wasm low level exception mechanism.

src/frames.cc

Index: src/frames.cc
diff --git a/src/frames.cc b/src/frames.cc
index 117f63ce3f471ee777b933f236e24b6fb1eb9a85..470601e5b4b407bb6b05e4c377b2d458728684ac 100644
--- a/src/frames.cc
+++ b/src/frames.cc
@@ -1477,6 +1477,15 @@ Script* WasmFrame::script() const {
   return wasm::WasmDebugInfo::GetFunctionScript(debug_info, function_index());
 }
 
+int WasmFrame::LookupExceptionHandlerInTable(int* stack_slots) {
+  DCHECK_NOT_NULL(stack_slots);
+  Code* code = LookupCode();
+  HandlerTable* table = HandlerTable::cast(code->handler_table());
+  int pc_offset = static_cast<int>(pc() - code->entry());
+  *stack_slots = code->stack_slots();
+  return table->LookupReturn(pc_offset);
+}
+
 namespace {