Improve error message on build failure

[masci]

Fixes #527

At some point, deep into the legacy package, some function returns an error with an empty message, causing the command to fail in suspense with "Error during build: build failed: .

This is a workaround, the real fix would be going on a quest in search of the command(s) returning the empty error.

[federicobond]

Change LGTM. The errors with missing messages can be found here:

arduino-cli/legacy/builder/phases/sizer.go

Lines 106 to 114 in 7e547b0

	if textSize > maxTextSize {
	logger.Println(constants.LOG_LEVEL_ERROR, constants.MSG_SIZER_TEXT_TOO_BIG)
	return errors.New("")
	}
	if maxDataSize > 0 && dataSize > maxDataSize {
	logger.Println(constants.LOG_LEVEL_ERROR, constants.MSG_SIZER_DATA_TOO_BIG)
	return errors.New("")
	}

If you want, I can submit a pull request adding proper messages along the lines of "text/data section exceeds available space in board" .

[masci]

@federicobond thanks a ton for pointing me to the error, it was faster for me to just fix it in this PR but I've used your suggestion regarding the message. I've also removed the workaround if err.Error() == "".