Make UTF-8 encoding of unpaired surrogates match Encoding standard

LayoutTests/fast/encoding/api/surrogate-pairs-expected.txt

 Test invalid UTF-16 surrogate pairs with UTF-8 encoding
 
 On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE".
 
 
-encoded = new TextEncoder('utf-8').encode("abc123")
-decoded = new TextDecoder('utf-8').decode(encoded)
-PASS decoded is "abc123"
+encoded = new TextEncoder('utf-8').encode('abc123')
+PASS JSON.stringify([].slice.call(encoded)) is "[97,98,99,49,50,51]"
 
-encoded = new TextEncoder('utf-8').encode("���")
-decoded = new TextDecoder('utf-8').decode(encoded)
-FAIL decoded should be �. Was ���.
+encoded = new TextEncoder('utf-8').encode('\ud800')
+PASS JSON.stringify([].slice.call(encoded)) is "[239,191,189]"
 
-encoded = new TextEncoder('utf-8').encode("���")
-decoded = new TextDecoder('utf-8').decode(encoded)
-FAIL decoded should be �. Was ���.
+encoded = new TextEncoder('utf-8').encode('\udc00')
+PASS JSON.stringify([].slice.call(encoded)) is "[239,191,189]"
 
-encoded = new TextEncoder('utf-8').encode("abc���def")
-decoded = new TextDecoder('utf-8').decode(encoded)
-FAIL decoded should be abc�def. Was abc���def.
+encoded = new TextEncoder('utf-8').encode('abc\ud800123')
+PASS JSON.stringify([].slice.call(encoded)) is "[97,98,99,239,191,189,49,50,51]"
 
-encoded = new TextEncoder('utf-8').encode("abc���def")
-decoded = new TextDecoder('utf-8').decode(encoded)
-FAIL decoded should be abc�def. Was abc���def.
+encoded = new TextEncoder('utf-8').encode('abc\udc00123')
+PASS JSON.stringify([].slice.call(encoded)) is "[97,98,99,239,191,189,49,50,51]"
 
-encoded = new TextEncoder('utf-8').encode("������")
-decoded = new TextDecoder('utf-8').decode(encoded)
-FAIL decoded should be ��. Was ������.
+encoded = new TextEncoder('utf-8').encode('\udc00\ud800')
+PASS JSON.stringify([].slice.call(encoded)) is "[239,191,189,239,191,189]"
 
 PASS successfullyParsed is true
 
 TEST COMPLETE