compiler: fix check for pointer in Temporary_reference_expression

The check for an unrepresentable pointer in
Temporary_reference_expression::do_get_backend was incorrectly
translated from C to Go in https://golang.org/cl/14346043.  Fix the
check to use points_to rather than has_pointer and deref.  This should
not make any difference in practice as either way the condition will
only be true for a pointer to void, but points_to is correct and more
efficient.

Change-Id: Iaeec7541a74b75a92991670f403ff13c20211afa
Reviewed-on: https://go-review.googlesource.com/38009
Reviewed-by: Than McIntosh <thanm@google.com>
1 file changed