Make __proto__ a foreign callback on Object.prototype.

test/test262/test262.status

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@@ skipping 12 matching lines @@
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 prefix test262
 def FAIL_OK = FAIL, OKAY
 
 ############################### BUGS ###################################
 
-# '__proto__' should be treated as a normal property in JSON.
-S15.12.2_A1: FAIL
-
 # Sequencing of getter side effects on receiver and argument properties
 # is wrong. The receiver callback should be called before any arguments
 # are evaluated.
 # V8 Bug: http://code.google.com/p/v8/issues/detail?id=691
 11.2.3-3_3: FAIL
 
 # Strings that are considered canonically equivalent by the Unicode standard
 # return a non-zero value on String.prototype.localeCompare calls.
 # V8 Bug: http://code.google.com/p/v8/issues/detail?id=2413
 15.5.4.9_CE: FAIL
@@ skipping 40 matching lines @@
 # compilation of parenthesized function literals. Needs investigation.
 S13.2.1_A1_T1: SKIP
 
 # BUG(3251225): Tests that timeout with --nocrankshaft.
 S15.1.3.1_A2.4_T1: SKIP
 S15.1.3.1_A2.5_T1: SKIP
 S15.1.3.2_A2.4_T1: SKIP
 S15.1.3.2_A2.5_T1: SKIP
 S15.1.3.3_A2.3_T1: SKIP
 S15.1.3.4_A2.3_T1: SKIP