Merge bitcoin-core/gui#729: test: Add missed header

36e2d51 qt, test: Add missed header (Hennadii Stepanov)

Pull request description:

  Should fix MSVC link errors like [that](https://api.cirrus-ci.com/v1/task/4870882892447744/logs/build.log):
  ```
  addressbooktests.obj : error LNK2019: unresolved external symbol "void __cdecl ConfirmMessage(class QString *,class std::chrono::duration<__int64,struct std::ratio<1,1000> >)" (?ConfirmMessage@@YAXPEAVQString@@v?$duration@_JU?$ratio@$00$0DOI@@std@@@chrono@std@@@z) referenced in function "void __cdecl `anonymous namespace'::EditAddressAndSubmit(class EditAddressDialog *,class QString const &,class QString const &,class QString)" (?EditAddressAndSubmit@?A0x2e52698e@@YAXPEAVEditAddressDialog@@AEBVQString@@1v3@@z) [C:\Users\ContainerAdministrator\AppData\Local\Temp\cirrus-ci-build\build_msvc\test_bitcoin-qt\test_bitcoin-qt.vcxproj]
  wallettests.obj : error LNK2001: unresolved external symbol "void __cdecl ConfirmMessage(class QString *,class std::chrono::duration<__int64,struct std::ratio<1,1000> >)" (?ConfirmMessage@@YAXPEAVQString@@v?$duration@_JU?$ratio@$00$0DOI@@std@@@chrono@std@@@z) [C:\Users\ContainerAdministrator\AppData\Local\Temp\cirrus-ci-build\build_msvc\test_bitcoin-qt\test_bitcoin-qt.vcxproj]
  C:\Users\ContainerAdministrator\AppData\Local\Temp\cirrus-ci-build\build_msvc\x64\Release\test_bitcoin-qt.exe : fatal error LNK1120: 1 unresolved externals [C:\Users\ContainerAdministrator\AppData\Local\Temp\cirrus-ci-build\build_msvc\test_bitcoin-qt\test_bitcoin-qt.vcxproj]
  ```

ACKs for top commit:
  fanquake:
    ACK 36e2d51

Tree-SHA512: 84685598fbf8857c0284ff660d953b93da3c2f47ba4ac0d3591b5009a6bcdb76898031fd70f289c4256ce389e485bd259ca145f9f862f085795e374dfa88705d

Author: hebasto

src/qt/test/util.cpp

@@ -2,6 +2,8 @@
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
+#include <qt/test/util.h>
+
 #include <chrono>
 
 #include <QApplication>

src/qt/test/util.h

@@ -7,6 +7,8 @@
 
 #include <chrono>
 
+#include <qglobal.h>
+
 QT_BEGIN_NAMESPACE
 class QString;
 QT_END_NAMESPACE