Don't recognize nullable function types as inlinable

#KT-19679 Fixed

compiler/backend/src/org/jetbrains/kotlin/codegen/inline/InlineCodegen.kt

@@ -529,7 +529,7 @@ abstract class InlineCodegen<out T: BaseExpressionCodegen>(
                 val varDescriptor = field.descriptor
                 //check that variable is inline function parameter
                 return !(varDescriptor is ParameterDescriptor &&
-                         InlineUtil.isInlineLambdaParameter(varDescriptor) &&
+                         InlineUtil.isInlineParameter(varDescriptor) &&
                          InlineUtil.isInline(varDescriptor.containingDeclaration))
             }
 
@@ -631,7 +631,7 @@ class PsiInlineCodegen(
         //TODO deparenthisise typed
         val deparenthesized = KtPsiUtil.deparenthesize(expression)
 
-        return InlineUtil.isInlineLambdaParameter(valueParameterDescriptor) && isInlinableParameterExpression(deparenthesized)
+        return InlineUtil.isInlineParameter(valueParameterDescriptor) && isInlinableParameterExpression(deparenthesized)
     }
 
     override fun genValueAndPut(

compiler/backend/src/org/jetbrains/kotlin/codegen/inline/defaultMethodUtil.kt

@@ -51,7 +51,7 @@ fun extractDefaultLambdaOffsetAndDescriptor(jvmSignature: JvmMethodSignature, fu
     val valueParameterOffset = valueParameters.takeWhile { it.kind != JvmMethodParameterKind.VALUE }.size
 
     return functionDescriptor.valueParameters.filter {
-        InlineUtil.isInlineLambdaParameter(it) && it.declaresDefaultValue()
+        InlineUtil.isInlineParameter(it) && it.declaresDefaultValue()
     }.associateBy {
         parameterOffsets[valueParameterOffset + it.index]
     }