Remove TypeSystemContext::mayBeTypeVariable optimization

It doesn't work now since anyway it's required to obtain type
constructor
At the same time, now it's not very expensive to obtain the constructor
since it's just a lookup tag

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/types/ConeInferenceContext.kt

@@ -263,11 +263,6 @@ interface ConeInferenceContext : TypeSystemInferenceExtensionContext, ConeTypeCo
         return this.typeConstructor
     }
 
-    override fun KotlinTypeMarker.mayBeTypeVariable(): Boolean {
-        require(this is ConeKotlinType)
-        return this.typeConstructor() is ConeTypeVariableTypeConstructor
-    }
-
     override fun CapturedTypeMarker.typeConstructorProjection(): TypeArgumentMarker {
         require(this is ConeCapturedType)
         return this.constructor.projection

compiler/resolution/src/org/jetbrains/kotlin/resolve/calls/components/ClassicTypeSystemContextForCS.kt

@@ -34,11 +34,6 @@ class ClassicTypeSystemContextForCS(override val builtIns: KotlinBuiltIns) : Typ
         return this.freshTypeConstructor
     }
 
-    override fun KotlinTypeMarker.mayBeTypeVariable(): Boolean {
-        require(this is KotlinType, this::errorMessage)
-        return this.constructor is TypeVariableTypeConstructor
-    }
-
     override fun createCapturedType(
         constructorProjection: TypeArgumentMarker,
         constructorSupertypes: List<KotlinTypeMarker>,

compiler/resolution/src/org/jetbrains/kotlin/resolve/calls/inference/components/ConstraintInjector.kt

@@ -219,7 +219,7 @@ class ConstraintInjector(
 
         // from AbstractTypeCheckerContextForConstraintSystem
         override fun isMyTypeVariable(type: SimpleTypeMarker): Boolean =
-            type.mayBeTypeVariable() && c.allTypeVariables.containsKey(type.typeConstructor())
+            c.allTypeVariables.containsKey(type.typeConstructor())
 
         override fun addUpperConstraint(typeVariable: TypeConstructorMarker, superType: KotlinTypeMarker) =
             addConstraint(typeVariable, superType, UPPER)

core/descriptors/src/org/jetbrains/kotlin/types/checker/ClassicTypeSystemContext.kt

@@ -401,10 +401,6 @@ interface ClassicTypeSystemContext : TypeSystemInferenceExtensionContext, TypeSy
         errorSupportedOnlyInTypeInference()
     }
 
-    override fun KotlinTypeMarker.mayBeTypeVariable(): Boolean {
-        errorSupportedOnlyInTypeInference()
-    }
-
     override fun CapturedTypeMarker.typeConstructorProjection(): TypeArgumentMarker {
         require(this is NewCapturedType, this::errorMessage)
         return this.constructor.projection

core/type-system/src/org/jetbrains/kotlin/types/model/TypeSystemContext.kt

@@ -155,8 +155,6 @@ interface TypeSystemInferenceExtensionContext : TypeSystemContext, TypeSystemBui
 
     fun TypeVariableMarker.freshTypeConstructor(): TypeConstructorMarker
 
-    fun KotlinTypeMarker.mayBeTypeVariable(): Boolean
-
     fun CapturedTypeMarker.typeConstructorProjection(): TypeArgumentMarker
     fun CapturedTypeMarker.typeParameter(): TypeParameterMarker?
     fun CapturedTypeMarker.withNotNullProjection(): KotlinTypeMarker