[wasm] Make the "jco" gdb macro also print WasmCode

Using the "jco" gdb macro on a WasmCode address would currently crash.
With this change, you can also use it to print code objects off the gc
heap.

R=titzer@chromium.org
CC=wasm-team@google.com

Bug: v8:7140, v8:6876
Change-Id: I21daf58b6b4734e3d052b66284b95938b4f57d40
Reviewed-on: https://chromium-review.googlesource.com/796416Reviewed-by: Ben Titzer <titzer@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#49753}

src/objects-printer.cc

@@ -16,6 +16,7 @@
 #include "src/ostreams.h"
 #include "src/regexp/jsregexp.h"
 #include "src/transitions-inl.h"
+#include "src/wasm/wasm-heap.h"
 #include "src/wasm/wasm-objects-inl.h"
 
 namespace v8 {
@@ -1889,6 +1890,12 @@ extern void _v8_internal_Print_Object(void* object) {
 
 extern void _v8_internal_Print_Code(void* object) {
   i::Isolate* isolate = i::Isolate::Current();
+  i::wasm::WasmCode* wasm_code = isolate->wasm_code_manager()->LookupCode(
+      reinterpret_cast<i::Address>(object));
+  if (wasm_code) {
+    wasm_code->Print(isolate);
+    return;
+  }
   isolate->FindCodeObject(reinterpret_cast<i::Address>(object))->Print();
 }