X87: [turbofan] Support unboxed float and double stack parameters and add tests.

src/compiler/x87/instruction-selector-x87.cc

Index: src/compiler/x87/instruction-selector-x87.cc
diff --git a/src/compiler/x87/instruction-selector-x87.cc b/src/compiler/x87/instruction-selector-x87.cc
index 04a7d5a09af40ebb8787c354b7e702ceaee64654..c1c1e5339becb7d07ec2558d4f84be870452f811 100644
--- a/src/compiler/x87/instruction-selector-x87.cc
+++ b/src/compiler/x87/instruction-selector-x87.cc
@@ -853,6 +853,7 @@ void InstructionSelector::VisitCall(Node* node, BasicBlock* handler) {
     // Push any stack arguments.
     for (Node* input : base::Reversed(buffer.pushed_nodes)) {
       // TODO(titzer): handle pushing double parameters.
+      if (input == nullptr) continue;
       InstructionOperand value =
           g.CanBeImmediate(input)
               ? g.UseImmediate(input)