Clean up transformations after #714.

Since now we have runtime helper, we don't need
expression -> statement conversions anymore.

test/fixtures/transformation/es6-tail-call/call-apply/expected.js

@@ -5,9 +5,5 @@
     console.log(this, arguments);
     return "foo";
   }
-  if (Math.random() > 0.5) {
-    return to5Runtime.tailCall(f.call, [this, n - 1], f);
-  } else {
-    return to5Runtime.tailCall(f.apply, [this, [n - 1]], f);
-  }
+  return Math.random() > 0.5 ? to5Runtime.tailCall(f.call, [this, n - 1], f) : to5Runtime.tailCall(f.apply, [this, [n - 1]], f);
 })(1000000) === "foo";

test/fixtures/transformation/es6-tail-call/cross-function/actual.js

@@ -1,7 +1,7 @@
 function f(n) {
-    return n <= 0 ? "foo" : g(n - 1);
+  return n <= 0 ? "foo" : g(n - 1);
 }
 
 function g(n) {
-    return n <= 0 ? "goo" : f(n - 1);
+  return n <= 0 ? "goo" : f(n - 1);
 }

test/fixtures/transformation/es6-tail-call/cross-function/expected.js

@@ -1,17 +1,9 @@
 "use strict";
 
 function f(n) {
-    if (n <= 0) {
-        return "foo";
-    } else {
-        return to5Runtime.tailCall(g, [n - 1]);
-    }
+  return n <= 0 ? "foo" : to5Runtime.tailCall(g, [n - 1]);
 }
 
 function g(n) {
-    if (n <= 0) {
-        return "goo";
-    } else {
-        return to5Runtime.tailCall(f, [n - 1]);
-    }
+  return n <= 0 ? "goo" : to5Runtime.tailCall(f, [n - 1]);
 }

test/fixtures/transformation/es6-tail-call/expressions/expected.js

@@ -1,18 +1,5 @@
 "use strict";
 
 (function f(n) {
-  var _temp;
-  if (n <= 0) {
-    return "foo";
-  } else {
-    doSmth();
-
-    if (!(_temp = getTrueValue())) {
-      return _temp;
-    }
-    if (_temp = getFalseValue()) {
-      return _temp;
-    }
-    return to5Runtime.tailCall(f, [n - 1]);
-  }
+  return n <= 0 ? "foo" : (doSmth(), getTrueValue() && (getFalseValue() || to5Runtime.tailCall(f, [n - 1])));
 })(1000000, true) === "foo";

test/fixtures/transformation/es6-tail-call/side-effect/actual.js

@@ -1,5 +1,5 @@
 function f() {
-    return getObj().method();
+  return getObj().method();
 }
 
 function g() {

test/fixtures/transformation/es6-tail-call/side-effect/expected.js

@@ -6,9 +6,5 @@ function f() {
 }
 
 function g() {
-  var _temp;
-  if (_temp = getFalseValue()) {
-    return _temp;
-  }
-  return to5Runtime.tailCall(getValue);
+  return getFalseValue() || to5Runtime.tailCall(getValue);
 }