[Death Knight] guard lesser ghoul expression parsing

[Harmenszoon]

Summary

• Guard Death Knight lesser_ghoul.* expression parsing before reading missing split segments.
• Return zero for lesser_ghoul.oldest.remains when no lesser ghoul is active.

Cause

death_knight_t::create_expression() handled any expression beginning with lesser_ghoul but read splits[1] and sometimes splits[2] before confirming those segments existed. The same parser also built lesser_ghoul.oldest.remains by reading active_lesser_ghouls[0], which is empty before the first lesser ghoul is active and after all lesser ghouls despawn.

active_lesser_ghouls is populated in lesser_ghoul_pet_t::arise() and erased in demise(), so an empty list is a normal state. Returning zero for oldest.remains matches the inactive/remains behavior used by nearby expressions such as active Death and Decay remains.

Validation

• Rebuilt build-fast with MSVC/Ninja through VsDevCmd.bat.
• Before fix: build-fast/simc.exe profiles/MID1/MID1_Death_Knight_Blood.simc actions=/wait,sec=1,if=lesser_ghoul iterations=1 target_error=0 cleanup_threads=1 aborted in fmt\base.h:433.
• Before fix: build-fast/simc.exe profiles/MID1/MID1_Death_Knight_Blood.simc actions=/wait,sec=1,if=lesser_ghoul.oldest.remains iterations=1 target_error=0 cleanup_threads=1 exited with an access violation.
• After fix: build-fast/simc.exe profiles/MID1/MID1_Death_Knight_Blood.simc actions=/wait,sec=1,if=lesser_ghoul iterations=1 target_error=0 cleanup_threads=1 reports Unknown lesser_ghoul expression 'lesser_ghoul'.
• After fix: build-fast/simc.exe profiles/MID1/MID1_Death_Knight_Blood.simc actions=/wait,sec=1,if=lesser_ghoul.oldest iterations=1 target_error=0 cleanup_threads=1 reports Unknown lesser_ghoul expression 'lesser_ghoul.oldest'.
• After fix: build-fast/simc.exe profiles/MID1/MID1_Death_Knight_Blood.simc actions=/wait,sec=1,if=lesser_ghoul.oldest.remains iterations=1 target_error=0 cleanup_threads=1 output=NUL exits 0.
• Control: build-fast/simc.exe profiles/MID1/MID1_Death_Knight_Blood.simc actions=/wait,sec=1,if=lesser_ghoul.count iterations=1 target_error=0 cleanup_threads=1 output=NUL exits 0.
• Smoke: build-fast/simc.exe profiles/MID1/MID1_Death_Knight_Blood.simc iterations=1 target_error=0 cleanup_threads=1 output=NUL exits 0.
• Smoke: build-fast/simc.exe profiles/CI.simc iterations=10 target_error=0 cleanup_threads=1 output=NUL exits 0 with existing baseline warnings.

Risk

Low. This only tightens expression parser segment checks and handles the normal no-active-lesser-ghoul state for oldest.remains.

[nyterage]

this is old/dead code that should probably be deleted instead, as blizzard added a stacking buff counter for it.