PPC: Simplify pending message object handling.

Port d4696c48

Original commit message:
This moves the decision whether to report a message or not to when
the pending exception is propagated instead of trying to preserve the
decision in a ThreadLocalTop field.

R=titzer@chromium.org

Review URL: https://codereview.chromium.org/998943003

Cr-Commit-Position: refs/heads/master@{#27150}

R=danno@chromium.org, svenpanne@chromium.org, titzer@chromium.org

BUG=

Review URL: https://codereview.chromium.org/1000963002

Cr-Commit-Position: refs/heads/master@{#27173}

src/ppc/full-codegen-ppc.cc

@@ -5330,26 +5330,12 @@ void FullCodeGenerator::EnterFinallyBlock() {
   __ mov(ip, Operand(pending_message_obj));
   __ LoadP(r4, MemOperand(ip));
   __ push(r4);
-
-  ExternalReference has_pending_message =
-      ExternalReference::address_of_has_pending_message(isolate());
-  __ mov(ip, Operand(has_pending_message));
-  __ lbz(r4, MemOperand(ip));
-  __ SmiTag(r4);
-  __ push(r4);
 }
 
 
 void FullCodeGenerator::ExitFinallyBlock() {
   DCHECK(!result_register().is(r4));
   // Restore pending message from stack.
-  __ pop(r4);
-  __ SmiUntag(r4);
-  ExternalReference has_pending_message =
-      ExternalReference::address_of_has_pending_message(isolate());
-  __ mov(ip, Operand(has_pending_message));
-  __ stb(r4, MemOperand(ip));
-
   __ pop(r4);
   ExternalReference pending_message_obj =
       ExternalReference::address_of_pending_message_obj(isolate());