[Turbofan] Make RegisterAllocatorVerifier tolerant of shared slots.

src/compiler/register-allocator-verifier.h

Index: src/compiler/register-allocator-verifier.h
diff --git a/src/compiler/register-allocator-verifier.h b/src/compiler/register-allocator-verifier.h
index 72e6e06e1333007090d919db9f590855c751a4a1..2db8af57287a794d373dbc02ad09373296d274e7 100644
--- a/src/compiler/register-allocator-verifier.h
+++ b/src/compiler/register-allocator-verifier.h
@@ -178,7 +178,6 @@ class RegisterAllocatorVerifier final : public ZoneObject {
     kFPRegister,
     kFixedFPRegister,
     kSlot,
-    kFPSlot,
     kFixedSlot,
     kNone,
     kNoneFP,
@@ -189,7 +188,9 @@ class RegisterAllocatorVerifier final : public ZoneObject {
 
   struct OperandConstraint {
     ConstraintType type_;
-    int value_;  // subkind index when relevant
+    // Constant or immediate value, register code, slot index, or slot size
+    // when relevant.
+    int value_;
     int spilled_slot_;
     int virtual_register_;
   };