Fix NullablePointer test utility

	* testsuite/util/testsuite_allocator.h (NullablePointer::operator bool):
	Fix return value.

From-SVN: r271189

libstdc++-v3/ChangeLog

+2019-05-14  Jonathan Wakely  <jwakely@redhat.com>
+
+	* testsuite/util/testsuite_allocator.h (NullablePointer::operator bool):
+	Fix return value.
+
 2019-05-14  Rainer Orth  <ro@CeBiTec.Uni-Bielefeld.DE>
 
 	* config/os/solaris/solaris2.10: Move to ...

libstdc++-v3/testsuite/util/testsuite_allocator.h

@@ -600,7 +600,7 @@ namespace __gnu_test
       NullablePointer() = default;
       NullablePointer(std::nullptr_t) noexcept : value() { }
 
-      explicit operator bool() const noexcept { return value == nullptr; }
+      explicit operator bool() const noexcept { return value != nullptr; }
 
       friend inline bool
       operator==(NullablePointer lhs, NullablePointer rhs) noexcept