[X87] [Ignition] Fix V8 x87 code generation bugs when Ingition was enabled.

  The CL #35926 (https://codereview.chromium.org/1804003002) exposed two hidden bugs in x87 code generation when Ignition was enabled.

  This CL fixed those bugs.

BUG=

Review-Url: https://codereview.chromium.org/1960993002
Cr-Commit-Position: refs/heads/master@{#36099}

src/crankshaft/x87/lithium-codegen-x87.cc

@@ -201,6 +201,13 @@ void LCodeGen::GenerateOsrPrologue() {
 
   osr_pc_offset_ = masm()->pc_offset();
 
+  // Interpreter is the first tier compiler now. It will run the code generated
+  // by TurboFan compiler which will always put "1" on x87 FPU stack.
+  // This behavior will affect crankshaft's x87 FPU stack depth check under
+  // debug mode.
+  // Need to reset the FPU stack here for this scenario.
+  __ fninit();
+
   // Adjust the frame size, subsuming the unoptimized frame into the
   // optimized frame.
   int slots = GetStackSlotCount() - graph()->osr()->UnoptimizedFrameSlots();

src/x87/builtins-x87.cc

@@ -654,6 +654,10 @@ void Builtins::Generate_InterpreterEntryTrampoline(MacroAssembler* masm) {
 
 
 void Builtins::Generate_InterpreterExitTrampoline(MacroAssembler* masm) {
+  // Interpreter handler is turbofanned code, need to reset the FPU before
+  // return
+  __ fninit();
+
   // The return value is in accumulator, which is already in eax.
 
   // Leave the frame (also dropping the register file).