For #83703

In #81718 we adjusted breakpoint display logic to show an 'empty' arrow on the
line, and the arrow with a dot at the column where the debugger is running.
However, not all debuggers support column breakpoints. Bowden noticed, while
working on his Python demo for ignite, that breakpoints in Python code no
longer displayed correctly.

This PR tweaks the logic so that if we see a breakpoint that doesn't have
an associated column, we show the arrow with a dot on the line, rather than
assuming that there'll be an inline indicator arrow.

Use isNaN instead of === NaN

Fixes #83654

Fixes #83702

This reverts commit 53d9528b.

* Adopt recursive fs.mkdir from node.js 12 (fix #82617)

* fix tests

Fixes #83801

Fixes #83798

Several fixes to terminal/tasks integration tests

See #83778 for follow up (when we're not in endgame)