JS: fix NPE in incremental compilation

Fix NPE when compiling project incrementally and a file which
is not recompiled contains try/catch statement

js/js.ast/src/org/jetbrains/kotlin/js/backend/ast/JsCatch.java

@@ -93,7 +93,7 @@ public class JsCatch extends SourceInfoAwareJsNode implements HasCondition {
     @NotNull
     @Override
     public JsCatch deepCopy() {
-        JsCatchScope scopeCopy = scope.copy();
+        JsCatchScope scopeCopy = scope != null ? scope.copy() : null;
         JsBlock bodyCopy = AstUtil.deepCopy(body);
         JsExpression conditionCopy = AstUtil.deepCopy(condition);
         JsParameter paramCopy = AstUtil.deepCopy(param);

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

@@ -3443,6 +3443,12 @@ public class BoxJsTestGenerated extends AbstractBoxJsTest {
             KotlinTestUtils.assertAllTestsPresentByMetadata(this.getClass(), new File("js/js.translator/testData/box/incremental"), Pattern.compile("^([^_](.+))\\.kt$"), TargetBackend.JS, true);
         }
 
+        @TestMetadata("catchScope.kt")
+        public void testCatchScope() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("js/js.translator/testData/box/incremental/catchScope.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("coroutines.kt")
         public void testCoroutines() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("js/js.translator/testData/box/incremental/coroutines.kt");

js/js.translator/testData/box/incremental/catchScope.kt

@@ -0,0 +1,16 @@
+// FILE: a.kt
+
+inline fun baz(): String =
+        try {
+            "OK"
+        }
+        catch (e: Exception) {
+            "not OK"
+        }
+
+// FILE: b.kt
+// RECOMPILE
+
+fun box(): String {
+    return baz()
+}