Add test suite to check wxGraphicsMatrix operations

Implemented tests of some basic operations like Invert() and Concat().

See #17670.

tests/test.bkl

@@ -181,6 +181,7 @@
             graphics/affinematrix.cpp
             graphics/boundingbox.cpp
             graphics/clippingbox.cpp
+            graphics/graphmatrix.cpp
             config/config.cpp
             controls/bitmapcomboboxtest.cpp
             controls/bitmaptogglebuttontest.cpp