Drop UniqueId from include/v8.h

test/cctest/test-api.cc

Index: test/cctest/test-api.cc
diff --git a/test/cctest/test-api.cc b/test/cctest/test-api.cc
index 2787e21d776407957fb84c3eb2e319fd984fe731..5bc94bc155e7818c2f7cd7855f868e7fc5760e27 100644
--- a/test/cctest/test-api.cc
+++ b/test/cctest/test-api.cc
@@ -82,7 +82,6 @@ using ::v8::String;
 using ::v8::Symbol;
 using ::v8::TryCatch;
 using ::v8::Undefined;
-using ::v8::UniqueId;
 using ::v8::V8;
 using ::v8::Value;