libstdc++: Fix some tests that fail with -fno-exceptions

libstdc++-v3/ChangeLog:

	* testsuite/18_support/nested_exception/rethrow_if_nested-term.cc:
	Require effective target exceptions_enabled instead of using
	dg-skip-if.
	* testsuite/23_containers/vector/capacity/constexpr.cc: Expect
	shrink_to_fit() to be a no-op without exceptions enabled.
	* testsuite/23_containers/vector/capacity/shrink_to_fit.cc:
	Likewise.
	* testsuite/ext/bitmap_allocator/check_allocate_max_size.cc:
	Require effective target exceptions_enabled.
	* testsuite/ext/malloc_allocator/check_allocate_max_size.cc:
	Likewise.
	* testsuite/ext/mt_allocator/check_allocate_max_size.cc:
	Likewise.
	* testsuite/ext/new_allocator/check_allocate_max_size.cc:
	Likewise.
	* testsuite/ext/pool_allocator/check_allocate_max_size.cc:
	Likewise.
	* testsuite/ext/throw_allocator/check_allocate_max_size.cc:
	Likewise.

libstdc++-v3/testsuite/18_support/nested_exception/rethrow_if_nested-term.cc

@@ -1,5 +1,5 @@
 // { dg-do run { target c++11 } }
-// { dg-skip-if "" { *-*-* } { "-fno-exceptions" } }
+// { dg-require-effective-target exceptions_enabled }
 
 #include <exception>
 #include <cstdlib>

libstdc++-v3/testsuite/23_containers/vector/capacity/constexpr.cc

@@ -89,11 +89,19 @@ test_shrink_to_fit()
   std::vector<int> v;
   v.reserve(9);
   v.shrink_to_fit();
+#if __cpp_exceptions
   VERIFY( v.capacity() == 0 );
+#else
+  VERIFY( v.capacity() == 9 );
+#endif
   v.reserve(9);
   v.resize(5);
   v.shrink_to_fit();
+#if __cpp_exceptions
   VERIFY( v.capacity() == v.size() );
+#else
+  VERIFY( v.capacity() == 9 );
+#endif
 
   return true;
 }

libstdc++-v3/testsuite/23_containers/vector/capacity/shrink_to_fit.cc

@@ -30,7 +30,11 @@ void test01()
   v.push_back(1);
   VERIFY( v.size() < v.capacity() );
   v.shrink_to_fit();
+#if __cpp_exceptions
   VERIFY( v.size() == v.capacity() );
+#else
+  VERIFY( v.size() < v.capacity() );
+#endif
 }
 
 int main()

libstdc++-v3/testsuite/ext/bitmap_allocator/check_allocate_max_size.cc

@@ -16,6 +16,8 @@
 // with this library; see the file COPYING3.  If not see
 // <http://www.gnu.org/licenses/>.
 
+// { dg-require-effective-target exceptions_enabled }
+
 // 20.4.1.1 allocator members
 
 #include <ext/bitmap_allocator.h>

libstdc++-v3/testsuite/ext/malloc_allocator/check_allocate_max_size.cc

@@ -16,6 +16,8 @@
 // with this library; see the file COPYING3.  If not see
 // <http://www.gnu.org/licenses/>.
 
+// { dg-require-effective-target exceptions_enabled }
+
 // 20.4.1.1 allocator members
 
 #include <ext/malloc_allocator.h>

libstdc++-v3/testsuite/ext/mt_allocator/check_allocate_max_size.cc

@@ -16,6 +16,8 @@
 // with this library; see the file COPYING3.  If not see
 // <http://www.gnu.org/licenses/>.
 
+// { dg-require-effective-target exceptions_enabled }
+
 // 20.4.1.1 allocator members
 
 #include <ext/mt_allocator.h>

libstdc++-v3/testsuite/ext/new_allocator/check_allocate_max_size.cc

@@ -16,6 +16,8 @@
 // with this library; see the file COPYING3.  If not see
 // <http://www.gnu.org/licenses/>.
 
+// { dg-require-effective-target exceptions_enabled }
+
 // 20.4.1.1 allocator members
 
 #include <ext/new_allocator.h>

libstdc++-v3/testsuite/ext/pool_allocator/check_allocate_max_size.cc

@@ -16,6 +16,8 @@
 // with this library; see the file COPYING3.  If not see
 // <http://www.gnu.org/licenses/>.
 
+// { dg-require-effective-target exceptions_enabled }
+
 // 20.4.1.1 allocator members
 
 #include <ext/pool_allocator.h>

libstdc++-v3/testsuite/ext/throw_allocator/check_allocate_max_size.cc

@@ -18,6 +18,7 @@
 
 // { dg-require-time "" }
 // { dg-require-cstdint "" }
+// { dg-require-effective-target exceptions_enabled }
 
 #include <ext/throw_allocator.h>
 #include <testsuite_allocator.h>