Handle proxies in KeyedStoreIC::Store, instead of just ignoring them.

test/mjsunit/harmony/proxies.js

Index: test/mjsunit/harmony/proxies.js
diff --git a/test/mjsunit/harmony/proxies.js b/test/mjsunit/harmony/proxies.js
index 401fa0d9281ce5582988d6cc004654486bd12078..13ce32b7c219e09505055f3d399a1e874aab2a90 100644
--- a/test/mjsunit/harmony/proxies.js
+++ b/test/mjsunit/harmony/proxies.js
@@ -350,6 +350,13 @@ function TestSet2(create, handler) {
   assertEquals(44, p[77] = 44)
   assertEquals("77", key)
   assertEquals(44, val)
+
+  assertEquals(45, (function(n) { return p[n] = 45 })("c"))
+  assertEquals("c", key)
+  assertEquals(45, val)
+  assertEquals(46, (function(n) { return p[n] = 46 })(99))
+  assertEquals("99", key)
+  assertEquals(46, val)
 }
 
 TestSet({