Fix a few preprocessor macros that could capture an 'else'.

Fix a few preprocessor macros that could capture an 'else'.

Namely they are SLOW_ASSERT, RETURN_IF_SCHEDULED_EXCEPTION, and
RETURN_IF_EMTPY_HANDLE_VALUE.

R=svenpanne@chromium.org
BUG=
TEST=

Committed: http://code.google.com/p/v8/source/detail?r=10329

[Sven Panne, 2012-01-04 13:19:48]

LGTM with nits

http://codereview.chromium.org/8983016/diff/1/src/isolate.h
File src/isolate.h (right):

http://codereview.chromium.org/8983016/diff/1/src/isolate.h#newcode111
src/isolate.h:111: if (isolate->has_scheduled_exception()) {         \
We should probably always use parentheses around arguments in macros to avoid
surprises regarding operator predences. Furthermore, "isolate" is used twice in
the expansion, so using a temp variable for it (with an unlikely name, hygienic
macros FTW!!) is a bit safer.

http://codereview.chromium.org/8983016/diff/1/src/isolate.h#newcode118
src/isolate.h:118: if (call.is_null()) {                                  \
Parentheses again in this macro...

[Kevin Millikin (Chromium), 2012-01-04 13:52:03]

Thanks for the comments.  Please take another quick look.

[Sven Panne, 2012-01-04 14:24:41]

lgtm