c++: Allow new char[4]{"foo"} [PR77841]

c++: Allow new char[4]{"foo"} [PR77841]

Currently, we allow new char[]{"foo"}, but not new char[4]{"foo"}.
We should accept the latter too: [dcl.init.list]p3.3 says to treat
this as [dcl.init.string].

We were rejecting this code because we never called reshape_init before
the digest_init in build_new_1.  reshape_init handles [dcl.init.string]
by unwrapping the STRING_CST from its enclosing { }, and digest_init
assumes that reshape_init has been called for aggregates anyway, and an
array is an aggregate.

gcc/cp/ChangeLog:

	PR c++/77841
	* init.c (build_new_1): Call reshape_init.

gcc/testsuite/ChangeLog:

	PR c++/77841
	* g++.dg/cpp0x/initlist-new4.C: New test.