Introduce new function 'takeIf' to replace value with null if it doesn't match the predicate.

#KT-7858

libraries/stdlib/src/kotlin/util/Standard.kt

@@ -61,6 +61,13 @@ public inline fun <T> T.also(block: (T) -> Unit): T { block(this); return this }
 @kotlin.internal.InlineOnly
 public inline fun <T, R> T.let(block: (T) -> R): R = block(this)
 
+/**
+ * Returns `this` value if it satisfies the given [predicate] or `null`, if it doesn't.
+ */
+@kotlin.internal.InlineOnly
+@SinceKotlin("1.1")
+public inline fun <T> T.takeIf(predicate: (T) -> Boolean): T? = if (predicate(this)) this else null
+
 /**
  * Executes the given function [action] specified number of [times].
  *