Language Server crashes on Windows after code upload and related board COM port re-assignment

[rsora]

Describe the bug
On windows, uploading code on an arduino:samd board like the MKR1010, I see an error popup from the language server after the upload, probably caused by multiple restarts of the LS triggered by a COM port change for the board (please see the entire screencast)

To Reproduce
Steps to reproduce the behavior:

1. Connect a MKR1010 (or any other SAMD board) and select the board in the board selector drop down
2. Open a sketch
3. Press upload
4. See error after the board changes its COM port

Expected behavior
LS should not crash

Screenshots

Desktop (please complete the following information):

• OS: Windows 10
• Version: 2.0.0-beta.1-snapshot.9e35571
• Date: 2021-02-12T08:28:48.914Z
• CLI Version: nightly-20210212 alpha [560025a6]

Additional context
@cmaglie could you please double check the LS logs attached to the issue and verify if there could be issues also in the Language Server?
sketch_feb12a.zip

[rsora]

Me and @cmaglie took a look in the LS logs and it seems that the panic you see in the logs in the attachment is not the root cause of the Issue.

2021/02/12 11:37:34 Panic: runtime error: invalid memory address or nil pointer dereference

goroutine 34 [running]:
runtime/debug.Stack(0xad61fe, 0x2, 0xc0002d9630)
	C:/hostedtoolcache/windows/go/1.13.15/x64/src/runtime/debug/stack.go:24 +0xa4
github.com/bcmi-labs/arduino-language-server/streams.CatchAndLogPanic()
	D:/a/arduino-language-server/arduino-language-server/streams/panics.go:14 +0xc6
panic(0xa092e0, 0xfd5f20)
	C:/hostedtoolcache/windows/go/1.13.15/x64/src/runtime/panic.go:679 +0x1c0
github.com/arduino/go-paths-helper.(*Path).String(...)
	C:/Users/runneradmin/go/pkg/mod/github.com/arduino/go-paths-helper@v1.5.0/paths.go:565
github.com/bcmi-labs/arduino-language-server/handler.(*InoHandler).generateBuildEnvironment(0xc00023e140, 0x0, 0x0, 0x0)
	D:/a/arduino-language-server/arduino-language-server/handler/builder.go:121 +0x4dd
github.com/bcmi-labs/arduino-language-server/handler.(*InoHandler).initializeWorkbench(0xc00023e140, 0xbb4ee0, 0xc00001e198, 0xc00028a000, 0x0, 0x0)
	D:/a/arduino-language-server/arduino-language-server/handler/handler.go:537 +0x1bb
github.com/bcmi-labs/arduino-language-server/handler.(*InoHandler).HandleMessageFromIDE.func1(0xc00023e140, 0xbb4ee0, 0xc00001e198, 0xc00028a000)
	D:/a/arduino-language-server/arduino-language-server/handler/handler.go:258 +0x180
created by github.com/bcmi-labs/arduino-language-server/handler.(*InoHandler).HandleMessageFromIDE
	D:/a/arduino-language-server/arduino-language-server/handler/handler.go:249 +0x2fcf

I'm going to assign this to @kittaakos, but please @cmaglie, be available for assistance 😃

[kittaakos]

Related: golang/vscode-go@1ad5c33