Unify handling of <color> for SVG/non-SVG properties

LayoutTests/svg/dom/rgb-color-parser-expected.txt

 This test fuzzes the color parser with semi-random attribute values and dumps the results of any values that parse successfully.
 
 On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE".
 
 
-Parsed as rgb(0, 0, 255): blue
+Parsed as blue: blue
 Parsed as rgb(0, 255, 0): rgb(0, 255, 0)
 Parsed as rgb(255, 255, 0): rgb(100%,100%,0%
 Failed to parse: rgba(100%,100%,0%
 Failed to parse: rgb(100%,100%,r)
 Failed to parse: rgb (100%,100%,r)
 Failed to parse: rgb(100%, 1, 1)
 Failed to parse: hsl(100%,100%,100%)
 Failed to parse: yello
 Failed to parse: !#fff
 Failed to parse: #sdf
 Failed to parse: #
 Failed to parse: #f
 Failed to parse: #ff
 Failed to parse: #ffff
 Failed to parse: #fffff
 Failed to parse: #fffffff
 Failed to parse: green,
 Parsed as rgb(0, 10, 20): rgb(0, 10, 20)
 Parsed as rgb(255, 255, 255): #fff
 Parsed as rgb(255, 255, 255): #ffffff
 Parsed as rgb(255, 255, 255): #FFF
 Parsed as rgb(255, 255, 255): #FFFFFF
-Parsed as rgb(0, 128, 0):  green
-Parsed as rgb(0, 128, 0): green 
-Parsed as rgb(0, 128, 0): green
+Parsed as green:  green
+Parsed as green: green 
+Parsed as green: green
 Failed to parse: rgb(.78-2e8e
 Failed to parse: rgb(% 
 Failed to parse: rgb(7
 Failed to parse: rgb(e+
 Failed to parse: rgb(
 Failed to parse: rgb( -2e9%0.795e0,).   
 Failed to parse: rgb(%,4+7).-(%+        8 
 Failed to parse: rgb(74).9 +(.% 0       635
 Failed to parse: rgb()9,- 8     7%4%9%%.
 Failed to parse: rgb(49),,4-30378 052
@@ skipping 238 matching lines @@
 Failed to parse: rgb(.27+
 Failed to parse: rgb(
 Failed to parse: 
 Failed to parse: 
 Failed to parse: rgb()
 Parsed as rgb(0, 255, 0): #0f0
 PASS successfullyParsed is true
 
 TEST COMPLETE