gh-101135: Add backwards compatibility to Windows launcher for older 32-bit versions (GH-101138)

Python 2.x and up to 3.4 did not contain the "-32" in their registry name, so the 32 and 64-bit installs were treated equal. Since 3.5/PEP 514 this is no longer true, but we still want to detect the EOL versions correctly in case people are still using them.

Additionally, the code to replace a node with one with a lower sort key was buggy (wrong node chosen, replace never happened since parent was always NULL, replaced node never freed, etc)