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

src/isolate.cc

Index: src/isolate.cc
diff --git a/src/isolate.cc b/src/isolate.cc
index cfb6860d978b1566005f430d7854bd224dc8e9bb..fd0ea5df17402521d225a050295be83f78644542 100644
--- a/src/isolate.cc
+++ b/src/isolate.cc
@@ -1149,8 +1149,8 @@
   Address handler_sp = nullptr;
   Address handler_fp = nullptr;
 
-  // Special handling of termination exceptions, uncatchable by JavaScript and
-  // Wasm code, we unwind the handlers until the top ENTRY handler is found.
+  // Special handling of termination exceptions, uncatchable by JavaScript code,
+  // we unwind the handlers until the top ENTRY handler is found.
   bool catchable_by_js = is_catchable_by_javascript(exception);
 
   // Compute handler and stack unwinding information by performing a full walk
@@ -1170,28 +1170,6 @@
       handler_sp = handler->address() + StackHandlerConstants::kSize;
       offset = Smi::cast(code->handler_table()->get(0))->value();
       break;
-    }
-
-    if (FLAG_wasm_eh_prototype) {
-      if (frame->is_wasm() && is_catchable_by_wasm(exception)) {
-        int stack_slots = 0;  // Will contain stack slot count of frame.
-        WasmFrame* wasm_frame = static_cast<WasmFrame*>(frame);
-        offset = wasm_frame->LookupExceptionHandlerInTable(&stack_slots);
-        if (offset >= 0) {
-          // Compute the stack pointer from the frame pointer. This ensures that
-          // argument slots on the stack are dropped as returning would.
-          Address return_sp = frame->fp() +
-                              StandardFrameConstants::kFixedFrameSizeAboveFp -
-                              stack_slots * kPointerSize;
-
-          // Gather information from the frame.
-          code = frame->LookupCode();
-
-          handler_sp = return_sp;
-          handler_fp = frame->fp();
-          break;
-        }
-      }
     }
 
     // For optimized frames we perform a lookup in the handler table.