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

#KT-6405 Fixed

idea/testData/refactoring/extractFunction/parameters/extractThis/explicitLabeledThisInMember.kt.after

@@ -19,6 +19,4 @@ public class A(): Z() {
     }
 }
 
-private fun i(a1: A, b1: A.B): Int {
-    return a1.a + b1.b + a1.z + b1.z
-}
+private fun i(a1: A, b1: A.B) = a1.a + b1.b + a1.z + b1.z

idea/testData/refactoring/extractFunction/parameters/extractThis/explicitThisInExtension.kt.after

@@ -7,6 +7,4 @@ fun Z.foo(): Int {
     return i() + 1
 }
 
-private fun Z.i(): Int {
-    return this.a
-}
+private fun Z.i() = this.a

idea/testData/refactoring/extractFunction/parameters/extractThis/explicitThisInMember.kt.after

@@ -19,6 +19,4 @@ public class A(): Z() {
     }
 }
 
-private fun i(a1: A, b1: A.B): Int {
-    return a1.a + b1.b + b1.z
-}
+private fun i(a1: A, b1: A.B) = a1.a + b1.b + b1.z

idea/testData/refactoring/extractFunction/parameters/extractThis/implicitAndExplicitLabeledThisInMember.kt.after

@@ -19,6 +19,4 @@ public class A(): Z() {
     }
 }
 
-private fun i(a1: A, b1: A.B): Int {
-    return a1.a + b1.b + a1.z + b1.z
-}
+private fun i(a1: A, b1: A.B) = a1.a + b1.b + a1.z + b1.z

idea/testData/refactoring/extractFunction/parameters/extractThis/implicitAndExplicitThisInExtension.kt.after

@@ -7,6 +7,4 @@ fun Z.foo(): Int {
     return i() + 1
 }
 
-private fun Z.i(): Int {
-    return this.a + a
-}
+private fun Z.i() = this.a + a

idea/testData/refactoring/extractFunction/parameters/extractThis/implicitThisInExtension.kt.after

@@ -7,6 +7,4 @@ fun Z.foo(): Int {
     return i() + 1
 }
 
-private fun Z.i(): Int {
-    return a
-}
+private fun Z.i() = a

idea/testData/refactoring/extractFunction/parameters/extractThis/implicitThisInMember.kt.after

@@ -19,6 +19,4 @@ public class A(): Z() {
     }
 }
 
-private fun i(a1: A, b1: A.B): Int {
-    return a1.a + b1.b + b1.z
-}
+private fun i(a1: A, b1: A.B) = a1.a + b1.b + b1.z

idea/testData/refactoring/extractFunction/parameters/extractThis/qualifiedThisAsArgument.kt.after

@@ -9,9 +9,7 @@ class A {
     fun B.foo() = i(this@A, this)
 }
 
-private fun i(a1: A, b: B): Int {
-    return a1.a + b.b
-}
+private fun i(a1: A, b: B) = a1.a + b.b
 
 class B {
     val b = 1