Replace CollectVariables with locals(), update callsites to walk locals instead

src/ast/variables.h

Index: src/ast/variables.h
diff --git a/src/ast/variables.h b/src/ast/variables.h
index bb757925e3fd81c109ac99af3c9c5ba327a356f5..1d6b33657069efd1b23960fed615fe533c90b08d 100644
--- a/src/ast/variables.h
+++ b/src/ast/variables.h
@@ -71,10 +71,6 @@ class Variable final : public ZoneObject {
   bool IsStackLocal() const { return location() == VariableLocation::LOCAL; }
   bool IsStackAllocated() const { return IsParameter() || IsStackLocal(); }
   bool IsContextSlot() const { return location() == VariableLocation::CONTEXT; }
-  bool IsGlobalSlot() const { return location() == VariableLocation::GLOBAL; }
-  bool IsUnallocatedOrGlobalSlot() const {
-    return IsUnallocated() || IsGlobalSlot();
-  }
   bool IsLookupSlot() const { return location() == VariableLocation::LOOKUP; }
   bool IsGlobalObjectProperty() const;
   bool IsStaticGlobalObjectProperty() const;