[crankshaft] Added checks to tail call instructions that we don't have to restore caller doubles.

src/crankshaft/ppc/lithium-codegen-ppc.cc

Index: src/crankshaft/ppc/lithium-codegen-ppc.cc
diff --git a/src/crankshaft/ppc/lithium-codegen-ppc.cc b/src/crankshaft/ppc/lithium-codegen-ppc.cc
index ffd32798d41a8ceef5b18460120f56e912f128fe..2737010de5b4a2031d388f2870f095f05b5c633d 100644
--- a/src/crankshaft/ppc/lithium-codegen-ppc.cc
+++ b/src/crankshaft/ppc/lithium-codegen-ppc.cc
@@ -3351,6 +3351,7 @@ void LCodeGen::DoApplyArguments(LApplyArguments* instr) {
 
   InvokeFlag flag = CALL_FUNCTION;
   if (instr->hydrogen()->tail_call_mode() == TailCallMode::kAllow) {
+    DCHECK(!info()->saves_caller_doubles());
     // TODO(ishell): drop current frame before pushing arguments to the stack.
     flag = JUMP_FUNCTION;
     ParameterCount actual(r3);
@@ -3841,6 +3842,7 @@ void LCodeGen::DoInvokeFunction(LInvokeFunction* instr) {
   bool is_tail_call = hinstr->tail_call_mode() == TailCallMode::kAllow;
 
   if (is_tail_call) {
+    DCHECK(!info()->saves_caller_doubles());
     ParameterCount actual(instr->arity());
     // It is safe to use r6, r7 and r8 as scratch registers here given that
     // 1) we are not going to return to caller function anyway,