Debugger: Fix compilation without tests

* Some functions were inside WITH_TESTS section.
* MSVC requires Perspective::Split to be explicitly exported.

Change-Id: I272cefc5c4f446415b2714595f8b398f8ce010a4
Reviewed-by: Christian Stenger <christian.stenger@theqtcompany.com>

src/plugins/debugger/debuggermainwindow.h

@@ -52,7 +52,7 @@ class ANALYZER_EXPORT Perspective
 public:
     enum SplitType { SplitVertical, SplitHorizontal, AddToTab };
 
-    class Split
+    class ANALYZER_EXPORT Split
     {
     public:
         Split() = default;