Debugger: Use qtHookData to extract Qt version when possible

This avoids inferior calls, i.e. is faster and more robust.

Task-number: QTCREATORBUG-14350
Change-Id: I9f21eda6e2e3950eaaca90a35afb885e76e789d8
Reviewed-by: Christian Stenger <christian.stenger@theqtcompany.com>

share/qtcreator/debugger/gdbbridge.py

@@ -811,6 +811,14 @@ class Dumper(DumperBase):
         return None
 
     def qtVersion(self):
+        try:
+            # Only available with Qt 5.3+
+            qtversion = int(gdb.parse_and_eval("((void**)&qtHookData)[2]"))
+            self.qtVersion = lambda: qtversion
+            return qtversion
+        except:
+            pass
+
         try:
             version = self.qtVersionString()
             (major, minor, patch) = version[version.find('"')+1:version.rfind('"')].split('.')