Fix "Should be replaced with Kotlin function" warnings

core/descriptors.jvm/src/org/jetbrains/kotlin/builtins/jvm/JavaToKotlinClassMap.kt

@@ -202,7 +202,7 @@ object JavaToKotlinClassMap : PlatformToKotlinClassMap {
 
         val kotlinMutableAnalogFqName = readOnlyToMutable[kotlinAnalog.fqNameUnsafe] ?: return setOf(kotlinAnalog)
 
-        return Arrays.asList(kotlinAnalog, builtIns.getBuiltInClassByFqName(kotlinMutableAnalogFqName))
+        return listOf(kotlinAnalog, builtIns.getBuiltInClassByFqName(kotlinMutableAnalogFqName))
     }
 
     override fun mapPlatformClass(classDescriptor: ClassDescriptor): Collection<ClassDescriptor> {

core/descriptors/src/org/jetbrains/kotlin/resolve/constants/constantValues.kt

@@ -91,7 +91,7 @@ class CharValue(value: Char) : IntegerValueConstant<Char>(value) {
         //TODO: KT-8507
         12.toChar() -> "\\f"
         '\r' -> "\\r"
-        else -> if (isPrintableUnicode(c)) Character.toString(c) else "?"
+        else -> if (isPrintableUnicode(c)) c.toString() else "?"
     }
 
     private fun isPrintableUnicode(c: Char): Boolean {

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

@@ -18,6 +18,7 @@ import org.jetbrains.kotlin.types.model.*
 import org.jetbrains.kotlin.types.model.CaptureStatus
 import org.jetbrains.kotlin.types.typeUtil.asTypeProjection
 import org.jetbrains.kotlin.types.typeUtil.contains
+import kotlin.math.max
 
 interface ClassicTypeSystemContext : TypeSystemInferenceExtensionContext {
     override fun TypeConstructorMarker.isDenotable(): Boolean {
@@ -470,7 +471,7 @@ private fun singleBestRepresentative(collection: Collection<KotlinType>) = colle
 internal fun UnwrappedType.typeDepthInternal() =
     when (this) {
         is SimpleType -> typeDepthInternal()
-        is FlexibleType -> Math.max(lowerBound.typeDepthInternal(), upperBound.typeDepthInternal())
+        is FlexibleType -> max(lowerBound.typeDepthInternal(), upperBound.typeDepthInternal())
     }
 
 internal fun SimpleType.typeDepthInternal(): Int {