Move TerminalInstance's process exit code message handling into a function and test

[Tyriar]

Move this into an exported function at the bottom of the file and add tests to cover all cases:

vscode/src/vs/workbench/contrib/terminal/browser/terminalInstance.ts

Lines 1338 to 1395 in 1bb8780

	let exitCodeMessage: string | undefined;
	// Create exit code message
	switch (typeof exitCodeOrError) {
	case 'number':
	// Only show the error if the exit code is non-zero
	this._exitCode = exitCodeOrError;
	if (this._exitCode === 0) {
	break;
	}
	let commandLine: string | undefined = undefined;
	if (this._shellLaunchConfig.executable) {
	commandLine = this._shellLaunchConfig.executable;
	if (typeof this._shellLaunchConfig.args === 'string') {
	commandLine += ` ${this._shellLaunchConfig.args}`;
	} else if (this._shellLaunchConfig.args && this._shellLaunchConfig.args.length) {
	commandLine += this._shellLaunchConfig.args.map(a => ` '${a}'`).join();
	}
	}
	if (this._processManager.processState === ProcessState.KilledDuringLaunch) {
	if (commandLine) {
	exitCodeMessage = nls.localize('launchFailed.exitCodeAndCommandLine', "The terminal process \"{0}\" failed to launch (exit code: {1}).", commandLine, this._exitCode);
	break;
	}
	exitCodeMessage = nls.localize('launchFailed.exitCodeOnly', "The terminal process failed to launch (exit code: {0}).", this._exitCode);
	break;
	}
	if (commandLine) {
	exitCodeMessage = nls.localize('terminated.exitCodeAndCommandLine', "The terminal process \"{0}\" terminated with exit code: {1}.", commandLine, this._exitCode);
	break;
	}
	exitCodeMessage = nls.localize('terminated.exitCodeOnly', "The terminal process terminated with exit code: {0}.", this._exitCode);
	break;
	case 'object':
	if (exitCodeOrError.message.toString().includes('Could not find pty with id')) {
	break;
	}
	this._exitCode = exitCodeOrError.code;
	const conptyError = exitCodeOrError.message.match(/.*error code:\s*(\d+).*$/);
	if (conptyError) {
	const errorCode = conptyError.length > 1 ? parseInt(conptyError[1]) : undefined;
	switch (errorCode) {
	case 5:
	exitCodeOrError.message = `Access was denied to the path containing your executable ${this.shellLaunchConfig.executable}. Manage and change your permissions to get this to work.`;
	break;
	case 267:
	exitCodeOrError.message = `Invalid starting directory ${this.initialCwd}, review your terminal.integrated.cwd setting`;
	break;
	case 1260:
	exitCodeOrError.message = `Windows cannot open this program because it has been prevented by a software restriction policy. For more information, open Event Viewer or contact your system Administrator`;
	break;
	}
	}
	exitCodeMessage = nls.localize('launchFailed.errorMessage', "The terminal process failed to launch: {0}.", exitCodeOrError.message);
	break;
	}