Task terminal marked failed for info/warning-level problems.

[elmar-peise]

A task's terminal status becomes "failed" with the hover message "Task has errors" when a problem matcher detected anything, including INFO and WARNING level problems:

vscode/src/vs/workbench/contrib/tasks/browser/taskTerminalStatus.ts

Lines 67 to 71 in eca7184

	if ((event.exitCode === 0) && (terminalData.problemMatcher.numberOfMatches === 0)) {
	terminalData.terminal.statusList.add(SUCCEEDED_TASK_STATUS);
	} else {
	terminalData.terminal.statusList.add(FAILED_TASK_STATUS);
	}

Can we instead either

1. purely rely on the task's exit code,
2. only consider it failed for ERROR level problems, or
3. introduce warning/info status indicators?

Let me know if this makes sense and I can prepare a PR.