my-lang: deferred analyses (was #38/#39/#40/#41) — blocked on ~330 LOC repro file

[hyperpolymath]

Consolidates #38, #39, #40, #41. All four require a ~330 LOC repro file that
is currently artefact-blocked. Reopens here as a single tracker so the
individual issues can close.

Inherited scope:

• Residual #14: obtain exact ~330 LOC repro + Windows ETW/-Z time-passes deep-dive #38: obtain ~330 LOC repro
• Obtain/Recover Exact ~330 LOC Repro File for Residual #14 #39: non-checker hypotheses on the same repro
• Deep-dive: ETW / -Z time-passes Allocator Profiling on Windows with Repro #40: ETW profiling on the same repro
• Investigation: Non-Checker Hypotheses for OOM and Artefact Divergence #41: re-analysis once Obtain/Recover Exact ~330 LOC Repro File for Residual #14 #39 returns

Status: parked. Will be unblocked when the repro file resurfaces.

Closes #38 #39 #40 #41 once filed.