Use alias_for with trivial property aliases

LayoutTests/fast/css/getComputedStyle/computed-style-expected.txt

Index: LayoutTests/fast/css/getComputedStyle/computed-style-expected.txt
diff --git a/LayoutTests/fast/css/getComputedStyle/computed-style-expected.txt b/LayoutTests/fast/css/getComputedStyle/computed-style-expected.txt
index 583ee68904516475c5848ee8fe1409fb14ff1fb9..4f17cdd9ccd72ab77fc3aea7d98cc26f8ceddd19 100644
--- a/LayoutTests/fast/css/getComputedStyle/computed-style-expected.txt
+++ b/LayoutTests/fast/css/getComputedStyle/computed-style-expected.txt
@@ -115,7 +115,6 @@ zoom: 1;
 -webkit-animation-play-state: running;
 -webkit-animation-timing-function: ease;
 -webkit-appearance: none;
--webkit-backface-visibility: visible;

[Timothy Loh, 2015/04/20 01:31:55]

alias_for properties are not enumerable

 -webkit-background-clip: border-box;
 -webkit-background-composite: source-over;
 -webkit-background-origin: padding-box;
@@ -133,7 +132,6 @@ zoom: 1;
 -webkit-box-orient: horizontal;
 -webkit-box-pack: start;
 -webkit-box-reflect: none;
--webkit-box-shadow: none;
 -webkit-column-break-after: auto;
 -webkit-column-break-before: auto;
 -webkit-column-break-inside: auto;
@@ -174,7 +172,6 @@ justify-content: start;
 -webkit-mask-size: auto;
 order: 0;
 -webkit-perspective: none;
--webkit-perspective-origin: 392px 288px;
 -webkit-print-color-adjust: economy;
 -webkit-rtl-ordering: logical;
 -webkit-text-combine: none;
@@ -188,8 +185,6 @@ order: 0;
 -webkit-text-stroke-color: rgb(0, 0, 0);
 -webkit-text-stroke-width: 0px;
 -webkit-transform: none;
--webkit-transform-origin: 392px 288px;
--webkit-transform-style: flat;
 -webkit-transition-delay: 0s;
 -webkit-transition-duration: 0s;
 -webkit-transition-property: all;