Fix false positive "Not-null extension receiver of inline function can be made nullable" with operator fun invoke

#KT-25786 Fixed

idea/src/org/jetbrains/kotlin/idea/inspections/RedundantNotNullExtensionReceiverOfInlineInspection.kt

@@ -66,7 +66,7 @@ class RedundantNotNullExtensionReceiverOfInlineInspection : AbstractKotlinInspec
                         }
                         is KtThisExpression -> {
                             val expectedType = context[BindingContext.EXPECTED_EXPRESSION_TYPE, it]
-                            expectedType != null && !expectedType.isNullable()
+                            it.parent is KtCallExpression || expectedType != null && !expectedType.isNullable()
                         }
                         is KtBinaryExpressionWithTypeRHS -> {
                             val type = context[BindingContext.TYPE, it.right]

idea/testData/inspections/redundantNotNullExtensionReceiverOfInline/test.kt

@@ -48,4 +48,12 @@ inline fun Int.bar(x: Int) = x - this // No problem
 inline fun Int.unary() = -this // No problem
 inline fun String.indexed(arg: Int) = this[arg] // No problem
 
+class Foo {
+    operator fun invoke() = Unit
+}
 
+inline fun Foo.bar() = this()
+
+inline fun Foo.bazz() = this.invoke()
+
+inline fun Foo.bazzz() = invoke()