PPC/s390: Clear exceptions in Invoke instead of JSEntryStub

Port cdae8654

Original commit message:

    A corresponding flag was added as well to help us find out what breaks when we
    do not clear pending exceptions on each JS entry.

R=jgruber@chromium.org, joransiu@ca.ibm.com, jyan@ca.ibm.com, michael_dawson@ca.ibm.com, mbrandy@us.ibm.com

BUG=5259
LOG=N

Review-Url: https://codereview.chromium.org/2208073003
Cr-Commit-Position: refs/heads/master@{#38312}

src/ppc/code-stubs-ppc.cc

@@ -1169,12 +1169,6 @@ void JSEntryStub::Generate(MacroAssembler* masm) {
   // restores all kCalleeSaved registers (including cp and fp) to their
   // saved values before returning a failure to C.
 
-  // Clear any pending exceptions.
-  __ mov(r8, Operand(isolate()->factory()->the_hole_value()));
-  __ mov(ip, Operand(ExternalReference(Isolate::kPendingExceptionAddress,
-                                       isolate())));
-  __ StoreP(r8, MemOperand(ip));
-
   // Invoke the function by calling through JS entry trampoline builtin.
   // Notice that we cannot store a reference to the trampoline code directly in
   // this stub, because runtime stubs are not traversed when doing GC.

src/s390/code-stubs-s390.cc

@@ -1150,12 +1150,6 @@ void JSEntryStub::Generate(MacroAssembler* masm) {
   // restores all kCalleeSaved registers (including cp and fp) to their
   // saved values before returning a failure to C.
 
-  // Clear any pending exceptions.
-  __ mov(ip, Operand(ExternalReference(Isolate::kPendingExceptionAddress,
-                                       isolate())));
-  __ mov(r7, Operand(isolate()->factory()->the_hole_value()));
-  __ StoreP(r7, MemOperand(ip));
-
   // Invoke the function by calling through JS entry trampoline builtin.
   // Notice that we cannot store a reference to the trampoline code directly in
   // this stub, because runtime stubs are not traversed when doing GC.