Prevent calls to ReturnValue::Set with pointer-valued types.

Prevent calls to ReturnValue::Set with pointer-valued types.

Currently, this code will compile:
  SomePointer* p = ...;
  ReturnValue r = ...;
  r.Set(p);

What happens is that ReturnValue::Set has no pointer-ish overloads, but
a bool one, and hence C++ will convert the pointer to a bool and use
the Set(bool) overload. In other words, the example above is equivalent
to: r.Set(p ? true : false); Which probably isn't what the author had
in mind. This change adds a Set(void*) overload whose body forces a
compile error, to prevent this from happening inadvertently. The only
use of this indeed turned out to be an error.

(Said error was fixed/removed in crrev.com/267393002.)

BUG=
R=dcarney@chromium.org

Committed: https://code.google.com/p/v8/source/detail?r=21217

[vogelheim, 2014-05-09 11:26:44]

Please have a look.

(Following crrev.com/267393002, this now compiles just fine in Chromium +
blink.)

[dcarney, 2014-05-09 11:30:41]

lgtm

[vogelheim, 2014-05-09 12:07:47]

Committed patchset #1 manually as r21217 (presubmit successful).

[vogelheim, 2014-05-09 12:17:55]

A revert of this CL has been created in
https://codereview.chromium.org/271113002/ by vogelheim@chromium.org.

The reason for reverting is: Looks like this broke the "V8 Linux64 ASAN" build..