Merge bitcoin#18646: gui: use PACKAGE_NAME in exception message

1b04302 gui: use PACKAGE_NAME in exception message (fanquake)

Pull request description:

  Should address [this comment](bitcoin#18643 (comment)).

  ![qt_exception](https://user-images.githubusercontent.com/863730/79310875-348bf780-7f2f-11ea-9970-ba1ac28c7849.png)

  Can be triggered with a diff like:
  ```diff
  diff --git a/src/qt/modaloverlay.cpp b/src/qt/modaloverlay.cpp
  index 6243a71..e5d499012 100644
  --- a/src/qt/modaloverlay.cpp
  +++ b/src/qt/modaloverlay.cpp
  @@ -6,6 +6,7 @@
   #include <qt/forms/ui_modaloverlay.h>

   #include <qt/guiutil.h>
  +#include <util/check.h>

   #include <chainparams.h>

  @@ -179,6 +180,7 @@ void ModalOverlay::showHide(bool hide, bool userRequested)

   void ModalOverlay::closeClicked()
   {
  +    CHECK_NONFATAL(false);
       showHide(true);
       userClosed = true;
   }
  ```
  and clicking close in the modal.
  ```bash
  EXCEPTION: 18NonFatalCheckError
  qt/modaloverlay.cpp:183 (closeClicked)
  Internal bug detected: 'false'
  You may report this issue here: https://github.com/bitcoin/bitcoin/issues
  ```

ACKs for top commit:
  jonasschnelli:
    Thanks. utACK 1b04302
  emilengler:
    utACK 1b04302
  hebasto:
    ACK 1b04302.

Tree-SHA512: 20118269882fbbb5602dafe8101c6ca6c92d7b97efc1ef280a68a83c6a58340018d05f837ecabefee618dc11a62e82828d5ecde4350a71a4c2fd24257b90d45c

Author: MarcoFalke

src/qt/bitcoin.cpp

@@ -381,7 +381,7 @@ void BitcoinApplication::shutdownResult()
 
 void BitcoinApplication::handleRunawayException(const QString &message)
 {
-    QMessageBox::critical(nullptr, "Runaway exception", BitcoinGUI::tr("A fatal error occurred. Bitcoin can no longer continue safely and will quit.") + QString("\n\n") + message);
+    QMessageBox::critical(nullptr, "Runaway exception", BitcoinGUI::tr("A fatal error occurred. %1 can no longer continue safely and will quit.").arg(PACKAGE_NAME) + QString("\n\n") + message);
     ::exit(EXIT_FAILURE);
 }