Fix some out-of-line constant pool garbage collection bugs.

src/arm/lithium-codegen-arm.cc

Index: src/arm/lithium-codegen-arm.cc
diff --git a/src/arm/lithium-codegen-arm.cc b/src/arm/lithium-codegen-arm.cc
index caeee042da417ff6af7af9dff7611c2737faa10a..aa8784c9b16f9df4f21bc2d6ca9506375814afbe 100644
--- a/src/arm/lithium-codegen-arm.cc
+++ b/src/arm/lithium-codegen-arm.cc
@@ -979,6 +979,10 @@ void LCodeGen::RecordSafepoint(
       safepoint.DefinePointerRegister(ToRegister(pointer), zone());
     }
   }
+  if (FLAG_enable_ool_constant_pool && (kind & Safepoint::kWithRegisters)) {
+    // Register pp always contains a pointer to the constant pool.
+    safepoint.DefinePointerRegister(pp, zone());
+  }
 }