Fix wxWrapSizer minimal size calculation.

Add a unit test checking that wxWrapSizer::CalcMin() returns the expected
results.

Closes #12464.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@66862 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

tests/test_test_gui.dsp

@@ -529,6 +529,10 @@ SOURCE=.\controls\windowtest.cpp
 # End Source File
 # Begin Source File
 
+SOURCE=.\sizers\wrapsizer.cpp
+# End Source File
+# Begin Source File
+
 SOURCE=.\xml\xrctest.cpp
 # End Source File
 # End Group