Make v8 compilable without V8_USE_UNSAFE_HANDLES.

Make v8 compilable without V8_USE_UNSAFE_HANDLES.

Without this modification, we get this error: "dereferencing type-punned pointer
will break strict-aliasing rules" (GCC strict aliasing).

Also included small CcTest sanity fixes: isolate() cannot return anything else
than default_isolate().

BUG=
TBR=svenpanne@chromium.org

Committed: https://code.google.com/p/v8/source/detail?r=14554

[dcarney, 2013-05-06 11:40:17]

https://codereview.chromium.org/14894006/diff/1/test/cctest/cctest.h
File test/cctest/cctest.h (right):

https://codereview.chromium.org/14894006/diff/1/test/cctest/cctest.h#newcode92
test/cctest/cctest.h:92: return context()->GetIsolate();
store the isolate instead when the context is set

https://codereview.chromium.org/14894006/diff/1/test/cctest/cctest.h#newcode95
test/cctest/cctest.h:95: // You need to have a valid HandleScope before calling
this function.
skip the comment

https://codereview.chromium.org/14894006/diff/1/test/cctest/cctest.h#newcode103
test/cctest/cctest.h:103: return
v8::Local<v8::Context>::New(v8::Isolate::GetCurrent(), context_);
use the context isolate
also, just inline this function

[marja, 2013-05-06 12:14:23]

https://codereview.chromium.org/14894006/diff/1/test/cctest/cctest.h
File test/cctest/cctest.h (right):

https://codereview.chromium.org/14894006/diff/1/test/cctest/cctest.h#newcode92
test/cctest/cctest.h:92: return context()->GetIsolate();
On 2013/05/06 11:40:17, dcarney wrote:
> store the isolate instead when the context is set

Removed this function, used default_isolate() instead, and made
set_default_isolate private. This was unnecessary, since isolate() cannot return
anything else than default_isolate_.

https://codereview.chromium.org/14894006/diff/1/test/cctest/cctest.h#newcode95
test/cctest/cctest.h:95: // You need to have a valid HandleScope before calling
this function.
On 2013/05/06 11:40:17, dcarney wrote:
> skip the comment

Done.

https://codereview.chromium.org/14894006/diff/1/test/cctest/cctest.h#newcode103
test/cctest/cctest.h:103: return
v8::Local<v8::Context>::New(v8::Isolate::GetCurrent(), context_);
On 2013/05/06 11:40:17, dcarney wrote:
> use the context isolate
> also, just inline this function

Done.

https://codereview.chromium.org/14894006/diff/1/test/cctest/cctest.h#newcode103
test/cctest/cctest.h:103: return
v8::Local<v8::Context>::New(v8::Isolate::GetCurrent(), context_);
On 2013/05/06 11:40:17, dcarney wrote:
> use the context isolate
> also, just inline this function

Done.

[dcarney, 2013-05-06 12:39:18]

lgtm

[dcarney, 2013-05-06 13:01:08]

Committed patchset #4 manually as r14554 (presubmit successful).