libstdc++: Require C++11 for 23_containers/vector/bool/110807.cc [PR110807]

This new test uses uniform initialization syntax, so requires C++11 or
later.

libstdc++-v3/ChangeLog:

	PR libstdc++/110807
	* testsuite/23_containers/vector/bool/110807.cc: Require c++11.

libstdc++-v3/testsuite/23_containers/vector/bool/110807.cc

 // { dg-options "-O2" }
-// { dg-do compile }
+// { dg-do compile { target c++11 } }
 
 // Bug 110807
 // Copy list initialisation of a vector<bool> raises a warning with -O2