Fix translation of copy() fun in data class

Fix translation of copy() function in data class which has secondary
constructor in JS BE. See KT-16717.

compiler/testData/codegen/box/dataClasses/copy/withSecondaryConstructor.kt

@@ -0,0 +1,9 @@
+data class A(val o: String, val k: String) {
+    constructor() : this("O", "k")
+}
+
+fun box(): String {
+    val a = A().copy(k = "K")
+    return a.o + a.k
+}
+

compiler/testData/codegen/light-analysis/dataClasses/copy/withSecondaryConstructor.txt

@@ -0,0 +1,21 @@
+@kotlin.Metadata
+public final class A {
+    private final @org.jetbrains.annotations.NotNull field k: java.lang.String
+    private final @org.jetbrains.annotations.NotNull field o: java.lang.String
+    public method <init>(): void
+    public method <init>(@org.jetbrains.annotations.NotNull p0: java.lang.String, @org.jetbrains.annotations.NotNull p1: java.lang.String): void
+    public final @org.jetbrains.annotations.NotNull method component1(): java.lang.String
+    public final @org.jetbrains.annotations.NotNull method component2(): java.lang.String
+    public synthetic static method copy$default(p0: A, p1: java.lang.String, p2: java.lang.String, p3: int, p4: java.lang.Object): A
+    public final @org.jetbrains.annotations.NotNull method copy(@org.jetbrains.annotations.NotNull p0: java.lang.String, @org.jetbrains.annotations.NotNull p1: java.lang.String): A
+    public method equals(p0: java.lang.Object): boolean
+    public final @org.jetbrains.annotations.NotNull method getK(): java.lang.String
+    public final @org.jetbrains.annotations.NotNull method getO(): java.lang.String
+    public method hashCode(): int
+    public method toString(): java.lang.String
+}
+
+@kotlin.Metadata
+public final class WithSecondaryConstructorKt {
+    public final static @org.jetbrains.annotations.NotNull method box(): java.lang.String
+}

compiler/tests-ir-jvm/tests/org/jetbrains/kotlin/codegen/ir/IrBlackBoxCodegenTestGenerated.java

@@ -5787,6 +5787,12 @@ public class IrBlackBoxCodegenTestGenerated extends AbstractIrBlackBoxCodegenTes
                 String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/dataClasses/copy/withGenericParameter.kt");
                 doTest(fileName);
             }
+
+            @TestMetadata("withSecondaryConstructor.kt")
+            public void testWithSecondaryConstructor() throws Exception {
+                String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/dataClasses/copy/withSecondaryConstructor.kt");
+                doTest(fileName);
+            }
         }
 
         @TestMetadata("compiler/testData/codegen/box/dataClasses/equals")

compiler/tests/org/jetbrains/kotlin/codegen/BlackBoxCodegenTestGenerated.java

@@ -5787,6 +5787,12 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
                 String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/dataClasses/copy/withGenericParameter.kt");
                 doTest(fileName);
             }
+
+            @TestMetadata("withSecondaryConstructor.kt")
+            public void testWithSecondaryConstructor() throws Exception {
+                String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/dataClasses/copy/withSecondaryConstructor.kt");
+                doTest(fileName);
+            }
         }
 
         @TestMetadata("compiler/testData/codegen/box/dataClasses/equals")

js/js.tests/test/org/jetbrains/kotlin/js/test/semantics/JsCodegenBoxTestGenerated.java

@@ -6520,6 +6520,12 @@ public class JsCodegenBoxTestGenerated extends AbstractJsCodegenBoxTest {
                 String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/dataClasses/copy/withGenericParameter.kt");
                 doTest(fileName);
             }
+
+            @TestMetadata("withSecondaryConstructor.kt")
+            public void testWithSecondaryConstructor() throws Exception {
+                String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/dataClasses/copy/withSecondaryConstructor.kt");
+                doTest(fileName);
+            }
         }
 
         @TestMetadata("compiler/testData/codegen/box/dataClasses/equals")

js/js.translator/src/org/jetbrains/kotlin/js/translate/declaration/JsDataClassGenerator.java

@@ -91,7 +91,8 @@ class JsDataClassGenerator extends DataClassMethodGenerator {
         }
 
         ClassDescriptor classDescriptor = (ClassDescriptor) function.getContainingDeclaration();
-        ClassConstructorDescriptor constructor = classDescriptor.getConstructors().iterator().next();
+        ClassConstructorDescriptor constructor = classDescriptor.getUnsubstitutedPrimaryConstructor();
+        assert constructor != null : "Data class should have primary constructor: " + classDescriptor;
 
         JsExpression constructorRef = context.getInnerReference(constructor);