reset pointer to prevent memory corruption

[cjihrig]

The code in path_resolver.c that replaces forward slashes with
backslashes on Windows did not work. It modified a chunk of
memory immediately following the memory it was meant to update.
This was leading to crashes on Windows in the Node.js test
suite ~1-2% of the time. This commit resets the pointer to the
correct location for the calculations.

Side note: this logic was broken and the slashes weren't actually
being updated, but the tests were still passing on Windows. This
logic might not really be needed after all?

Node.js stress test (4,000 runs spread across 4 windows machines): https://ci.nodejs.org/view/Stress/job/node-stress-single-test/73/ ✔️
Also resolves: nodejs/node#33403

[addaleax]

Almost all Windows APIs happily accept / as well as \, so yes, I guess it’s possible that this isn’t really needed? I guess the question is more whether paths that are processed this way end up being returned to WASM code and whether that code has specific expectations on the slashes?

[cjihrig]

This is related to host paths only. WASM, AFAIK, should only be dealing in Unix style paths, and the paths here shouldn't be exposed to WASM at any point.

[cjihrig]

@addaleax do you have any preference on landing this as is vs. removing the path translation?

[cjihrig]

I'm going to land this as is since the problem seems to be resolved. If it ends up causing any problems in the future it's easy enough to remove.