Use more correct check for the constructor symbol

- add test for extension function receiver

idea/idea-completion/testData/basic/common/primitiveCompletion/implicitReceiverFromExtensionMethod.kt

@@ -0,0 +1,14 @@
+class A {
+    fun aaa() {}
+    val aa = 10
+}
+
+fun A.aaaExt() {}
+
+fun A.test() {
+    <caret>
+}
+
+// EXIST: aaa
+// EXIST: aa
+// EXIST: aaaExt

idea/idea-completion/tests/org/jetbrains/kotlin/idea/completion/test/JSBasicCompletionTestGenerated.java

@@ -2277,6 +2277,11 @@ public class JSBasicCompletionTestGenerated extends AbstractJSBasicCompletionTes
                 runTest("idea/idea-completion/testData/basic/common/primitiveCompletion/implicitReceiverCompletion.kt");
             }
 
+            @TestMetadata("implicitReceiverFromExtensionMethod.kt")
+            public void testImplicitReceiverFromExtensionMethod() throws Exception {
+                runTest("idea/idea-completion/testData/basic/common/primitiveCompletion/implicitReceiverFromExtensionMethod.kt");
+            }
+
             @TestMetadata("localVariablesAndFunctions.kt")
             public void testLocalVariablesAndFunctions() throws Exception {
                 runTest("idea/idea-completion/testData/basic/common/primitiveCompletion/localVariablesAndFunctions.kt");

idea/idea-completion/tests/org/jetbrains/kotlin/idea/completion/test/JvmBasicCompletionTestGenerated.java

@@ -2277,6 +2277,11 @@ public class JvmBasicCompletionTestGenerated extends AbstractJvmBasicCompletionT
                 runTest("idea/idea-completion/testData/basic/common/primitiveCompletion/implicitReceiverCompletion.kt");
             }
 
+            @TestMetadata("implicitReceiverFromExtensionMethod.kt")
+            public void testImplicitReceiverFromExtensionMethod() throws Exception {
+                runTest("idea/idea-completion/testData/basic/common/primitiveCompletion/implicitReceiverFromExtensionMethod.kt");
+            }
+
             @TestMetadata("localVariablesAndFunctions.kt")
             public void testLocalVariablesAndFunctions() throws Exception {
                 runTest("idea/idea-completion/testData/basic/common/primitiveCompletion/localVariablesAndFunctions.kt");