Enable windows-debug github runner

[ohodson]

The windows-debug config exposed a UAF for the testUsvPtr() test in
the KJ_TEST("JavaScript USVStrings") since the debug build on Windows
overwrites freed memory which shows up as corruption if used after
free. The issue is described in #1334.

Fix: #1334
Test: bazel test -c dbg --cache_test_results=no //...

[dom96]

I wonder if we should also kill UsvStringPtr from our codebase to avoid falling into this trap again? or is it something that we cannot get rid of?

[ohodson]

I wonder if we should also kill UsvStringPtr from our codebase to avoid falling into this trap again? or is it something that we cannot get rid of?

@jasnell commented in #1334 (comment) that UsvString, and by extension UsvStringPtr are up for retirement.

I think the positive here is that the extra build config found an issue and will likely more of the same if they occur in future.

BTW, 100% open to a better fix if the folks more familiar with these bits see one.

[ohodson]

@dom96 , thanks for the review. 👍