Enhance _dl_catch_exception to allow disabling exception handling

In some cases, it is necessary to introduce noexcept regions
where raised dynamic loader exceptions (e.g., from lazy binding)
are fatal, despite being nested in a code region with an active
exception handler.  This change enhances _dl_catch_exception with
to provide such a capability.  The existing function is reused,
so that it is not necessary to introduce yet another function with
a similar purpose.

Change-Id: Iec1bf642ff95a349fdde8040e9baf851ac7b8904