Fix the definition of THREAD_CURRENT_IBASE_OFFSET.

The difference between between
art::Thread::tlsPtr_.mterp_current_ibase and
art::Thread::tlsPtr_.thread_local_objects is sizeof(size_t),
not sizeof(void*) (even if they have the same value on all
supported platforms/compilers in practice).

Test: ART host tests.
Change-Id: I70d196732499bd0cd073983de564547d08ee59ef
1 file changed