Introduce builder-like inference with an explicit opt-in for it

- Add marker for the experimental type inference features
 - Add annotation that will control builder-like inference
 - Require that annotation on corresponding parameters and extensions
 - Allow to use builder inference without suspendability

 Changes in tests and refactorings (rename mainly) are going to be
 introduced in further commits

libraries/stdlib/src/kotlin/annotations/Inference.kt

@@ -0,0 +1,18 @@
+/*
+ * Copyright 2010-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
+ */
+
+package kotlin
+
+import kotlin.annotation.AnnotationTarget.*
+import kotlin.experimental.ExperimentalTypeInference
+
+/**
+ * Marks the API which usages is dependent on the experimental builder inference.
+ */
+@Target(VALUE_PARAMETER, FUNCTION, PROPERTY)
+@Retention(AnnotationRetention.BINARY)
+@SinceKotlin("1.3")
+@ExperimentalTypeInference
+public annotation class BuilderInference

libraries/stdlib/src/kotlin/experimental/inferenceMarker.kt

@@ -0,0 +1,15 @@
+/*
+ * Copyright 2010-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
+ */
+
+package kotlin.experimental
+
+/**
+ * Marker of the use experimental type inference features
+ */
+@Experimental(level = Experimental.Level.ERROR)
+@Retention(AnnotationRetention.BINARY)
+@Target(AnnotationTarget.ANNOTATION_CLASS)
+@SinceKotlin("1.3")
+public annotation class ExperimentalTypeInference