S390: Fix storing to below stack to avoid sampler handler corrupting stored value

src/crankshaft/s390/lithium-codegen-s390.cc

Index: src/crankshaft/s390/lithium-codegen-s390.cc
diff --git a/src/crankshaft/s390/lithium-codegen-s390.cc b/src/crankshaft/s390/lithium-codegen-s390.cc
index 3c3e03c18b16702a22f5248dcc10eb4e2c62e75f..ac7d04e1086a4ae6eb4c5773772175c938325c46 100644
--- a/src/crankshaft/s390/lithium-codegen-s390.cc
+++ b/src/crankshaft/s390/lithium-codegen-s390.cc
@@ -5210,14 +5210,11 @@ void LCodeGen::DoClampTToUint8(LClampTToUint8* instr) {
 void LCodeGen::DoDoubleBits(LDoubleBits* instr) {
   DoubleRegister value_reg = ToDoubleRegister(instr->value());
   Register result_reg = ToRegister(instr->result());
-  // TODO(joransiu): Use non-memory version.
-  __ stdy(value_reg, MemOperand(sp, -kDoubleSize));
+  __ lgdr(result_reg, value_reg);
   if (instr->hydrogen()->bits() == HDoubleBits::HIGH) {
-    __ LoadlW(result_reg,
-              MemOperand(sp, -kDoubleSize + Register::kExponentOffset));
+    __ srlg(result_reg, result_reg, Operand(32));
   } else {
-    __ LoadlW(result_reg,
-              MemOperand(sp, -kDoubleSize + Register::kMantissaOffset));
+    __ llgfr(result_reg, result_reg);
   }
 }
 
@@ -5225,7 +5222,6 @@ void LCodeGen::DoConstructDouble(LConstructDouble* instr) {
   Register hi_reg = ToRegister(instr->hi());
   Register lo_reg = ToRegister(instr->lo());
   DoubleRegister result_reg = ToDoubleRegister(instr->result());
-  // TODO(joransiu): Construct with ldgr
   Register scratch = scratch0();
 
   // Combine hi_reg:lo_reg into a single 64-bit register.