Revert 6996, causes Mozilla debug failures on x64 with crankshaft.

Review URL: http://codereview.chromium.org/6594076

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@7003 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/x64/lithium-x64.cc

@@ -1725,6 +1725,7 @@ LInstruction* LChunkBuilder::DoLoadContextSlot(HLoadContextSlot* instr) {
 
 
 LInstruction* LChunkBuilder::DoStoreContextSlot(HStoreContextSlot* instr) {
+  Abort("Unimplemented: DoStoreContextSlot");  // Temporarily disabled (whesse).
   LOperand* context;
   LOperand* value;
   if (instr->NeedsWriteBarrier()) {