Sketch compiling via commandline does not check for valid primary .ino filename

When the Arduino IDE is invoked via the command line for a Verify or Upload task, such as when an external tool like [microsoft/vscode-arduino](/microsoft/vscode-arduino) invokes a build, but the name of the sketch file provided on the command line does not match its containing folder name, the first file from `FileUtils.listFiles` is used as the "primary" file, resulting in undefined behavior (the order returned by `listFiles` seems non-deterministic) and apparent obscure bugs such as the one I filed at microsoft/vscode-arduino#1100.

The requirement to have the `.ino` file match the folder name seems arbitrary and restrictive for command-line compilations when the IDE itself is not being used for development. I developed a simple fix for this on my own branch and plan on filing a PR.

Trace command-line Verify and Upload handling to the primary sketch selection and inspect how FileUtils.listFiles is used. Reproduce a sketch whose .ino filename differs from its containing folder, then verify that the selected primary file is valid and deterministic.

Written by the indexing model from the issue text.