has_value_dependent_address wasn't stripping location wrappers so it
gave the wrong answer for "&x" in the static_assert.  That led us to
thinking that the expression isn't instantiation-dependent, and we
skipped static initialization of A<0>::x.

This patch adds stripping so that has_value_dependent_address gives the
same answer as it used to before the location wrappers addition.

	* pt.c (has_value_dependent_address): Strip location wrappers.

	* g++.dg/cpp0x/constexpr-odr1.C: New test.
	* g++.dg/cpp0x/constexpr-odr2.C: New test.

From-SVN: r277266