Make snapshots reproducible.

src/x64/assembler-x64-inl.h

Index: src/x64/assembler-x64-inl.h
diff --git a/src/x64/assembler-x64-inl.h b/src/x64/assembler-x64-inl.h
index afac886c730e12fb6b26fe0b9746144987ecc933..ea32930ade9d6371db18764481ba78631363f3a1 100644
--- a/src/x64/assembler-x64-inl.h
+++ b/src/x64/assembler-x64-inl.h
@@ -370,6 +370,18 @@ void RelocInfo::set_target_cell(Cell* cell, WriteBarrierMode mode) {
 }
 
 
+void RelocInfo::WipeOut() {
+  if (IsEmbeddedObject(rmode_) || IsExternalReference(rmode_)) {
+    Memory::Address_at(pc_) = NULL;
+  } else if (IsCodeTarget(rmode_) || IsRuntimeEntry(rmode_)) {
+    // Effectively write zero into the relocation.
+    Assembler::set_target_address_at(pc_, pc_ + sizeof(int32_t));
+  } else {
+    UNREACHABLE();
+  }
+}
+
+
 bool RelocInfo::IsPatchedReturnSequence() {
   // The recognized call sequence is:
   //  movq(kScratchRegister, address); call(kScratchRegister);