Text origin was calculated incorrectly for the rotated text and the bounding box was wrong even in non-rotated case. Fix this by using correct definition of the text anchor according to the SVG specification and add a test to the svg sample demonstrating this. Closes #14489. git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@72494 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775