JVM IR: optimize type equality check on IR types

`AbstractTypeChecker.isCommonDenotableType` calls a few functions which
check if the type is flexible, which is not cheap in case of JVM IR, see
`asFlexibleType`.

 #KT-66281

core/compiler.common/src/org/jetbrains/kotlin/types/AbstractTypeChecker.kt

@@ -513,7 +513,7 @@ object AbstractTypeChecker {
     private fun TypeSystemContext.isCommonDenotableType(type: KotlinTypeMarker): Boolean =
         type.typeConstructor().isDenotable() &&
                 !type.isDynamic() && !type.isDefinitelyNotNullType() && !type.isNotNullTypeParameter() &&
-                type.lowerBoundIfFlexible().typeConstructor() == type.upperBoundIfFlexible().typeConstructor()
+                !type.isFlexibleWithDifferentTypeConstructors()
 
     fun effectiveVariance(declared: TypeVariance, useSite: TypeVariance): TypeVariance? {
         if (declared == TypeVariance.INV) return useSite

core/compiler.common/src/org/jetbrains/kotlin/types/model/TypeSystemContext.kt

@@ -448,6 +448,9 @@ interface TypeSystemContext : TypeSystemOptimizationContext {
     fun KotlinTypeMarker.lowerBoundIfFlexible(): SimpleTypeMarker = this.asFlexibleType()?.lowerBound() ?: this.asSimpleType()!!
     fun KotlinTypeMarker.upperBoundIfFlexible(): SimpleTypeMarker = this.asFlexibleType()?.upperBound() ?: this.asSimpleType()!!
 
+    fun KotlinTypeMarker.isFlexibleWithDifferentTypeConstructors(): Boolean =
+        lowerBoundIfFlexible().typeConstructor() != upperBoundIfFlexible().typeConstructor()
+
     fun TypeConstructorMarker.isDefinitelyClassTypeConstructor(): Boolean = isClassTypeConstructor() && !isInterface()
 
     fun KotlinTypeMarker.isFlexible(): Boolean = asFlexibleType() != null