Fix problem with empty vararg of boxed primitives in JVM_IR

When calling a generic Java generic method with vararg parameters with empty
vararg, incorrect array creation instruction was generated for primitive type:
NEWARRAY T_INT instead of ANEWARRAY java/lang/Integer. Here for Java method

  public static <T> void takesVarargOfT(T x1, T... xs) {}

corresponding vararg parameter was considered to be of type 'Array<T>?',
which is not a non-null array type, so, NewArray intrinsic failed to generate
proper bytecode.

compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/intrinsics/NewArray.kt

@@ -12,6 +12,7 @@ import org.jetbrains.kotlin.backend.jvm.ir.getArrayElementType
 import org.jetbrains.kotlin.codegen.inline.ReifiedTypeInliner
 import org.jetbrains.kotlin.ir.expressions.IrFunctionAccessExpression
 import org.jetbrains.kotlin.ir.types.isArray
+import org.jetbrains.kotlin.ir.types.isNullableArray
 import org.jetbrains.org.objectweb.asm.Type
 
 object NewArray : IntrinsicMethod() {
@@ -19,7 +20,7 @@ object NewArray : IntrinsicMethod() {
         codegen.gen(expression.getValueArgument(0)!!, Type.INT_TYPE, codegen.context.irBuiltIns.intType, data)
         return with(codegen) {
             val elementIrType = expression.type.getArrayElementType(context.irBuiltIns)
-            if (expression.type.isArray()) {
+            if (expression.type.isArray() || expression.type.isNullableArray()) {
                 putReifiedOperationMarkerIfTypeIsReifiedParameter(elementIrType, ReifiedTypeInliner.OperationKind.NEW_ARRAY)
                 mv.newarray(typeMapper.boxType(elementIrType))
             } else {

compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/lower/VarargLowering.kt

@@ -23,6 +23,7 @@ import org.jetbrains.kotlin.ir.declarations.IrFunction
 import org.jetbrains.kotlin.ir.declarations.IrPackageFragment
 import org.jetbrains.kotlin.ir.expressions.*
 import org.jetbrains.kotlin.ir.symbols.IrFunctionSymbol
+import org.jetbrains.kotlin.ir.types.makeNotNull
 import org.jetbrains.kotlin.ir.util.*
 import org.jetbrains.kotlin.util.capitalizeDecapitalize.toLowerCaseAsciiOnly
 
@@ -56,7 +57,7 @@ private class VarargLowering(val context: JvmBackendContext) : FileLoweringPass,
             val parameter = function.owner.valueParameters[i]
             if (parameter.varargElementType != null && !parameter.hasDefaultValue()) {
                 // Compute the correct type for the array argument.
-                val arrayType = parameter.type.substitute(expression.typeSubstitutionMap)
+                val arrayType = parameter.type.substitute(expression.typeSubstitutionMap).makeNotNull()
                 expression.putValueArgument(i, createBuilder().irArrayOf(arrayType))
             }
         }