Extraction Engine: Generate function/property accessor with expression body (whenever applicable)

#KT-6405 Fixed

idea/testData/refactoring/extractFunction/parameters/it/innerIt.kt.after

@@ -9,6 +9,4 @@ fun foo(t: Array<Array<Int>>) {
     }
 }
 
-private fun i(it: Int): Int {
-    return it + 1
-}
+private fun i(it: Int) = it + 1

idea/testData/refactoring/extractFunction/parameters/it/lambdaWithIt.kt.after

@@ -9,6 +9,4 @@ fun foo(t: Array<Int>) {
     }
 }
 
-private fun b(t: Array<Int>): Boolean {
-    return t.check { it + 1 > 1 }
-}
+private fun b(t: Array<Int>) = t.check { it + 1 > 1 }

idea/testData/refactoring/extractFunction/parameters/it/outerIt.kt.after

@@ -9,6 +9,4 @@ fun foo(t: Array<Array<Int>>) {
     }
 }
 
-private fun b(it: Array<Int>): Boolean {
-    return it.check { it + 1 > 1 }
-}
+private fun b(it: Array<Int>) = it.check { it + 1 > 1 }

idea/testData/refactoring/extractFunction/parameters/it/simpleIt.kt.after

@@ -9,6 +9,4 @@ fun foo(t: Array<Int>) {
     }
 }
 
-private fun i(it: Int): Int {
-    return it + 1
-}
+private fun i(it: Int) = it + 1