Fix: coverity warns of uncaught exception

Fix: coverity warns of uncaught exception

Coverity warns that some container operations used by
random_access_container_wrapper can throw even though methods are marked
as noexcept.

  CID 1512893 (#1-2 of 2): Uncaught exception (UNCAUGHT_EXCEPT)
  exn_spec_violation: An exception of type lttng::invalid_argument_error is thrown but the exception specification noexcept doesn't allow it to be thrown. This will result in a call to terminate().

The noexcept specifier is remvoved from operator* and end() of
random_access_container_wrapper's iterator implementation.

To make this a bit clearer, a bounds check is performed in operator[]
directly which will make errors easier to catch.

Reported-by: Coverity Scan
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Change-Id: I31d51e8709d33b3c80d64c8c05a23e519e3a93e7