Fix recording of BC_VARG. #2372

Job	Run time
LuaJIT (Linux/ARM64) Debug GC64:ON CC:gcc	4m 15s
LuaJIT (macOS/ARM64) Debug GC64:ON CC:clang	21s
LuaJIT (Linux/ARM64) Release GC64:ON CC:gcc	2m 28s
LuaJIT (macOS/ARM64) Release GC64:ON CC:clang	22s
LuaJIT (Linux/x86_64) Debug GC64:ON CC:gcc	3m 7s
LuaJIT (Linux/x86_64) Debug GC64:ON CC:clang	3m 15s
LuaJIT (macOS/x86_64) Debug GC64:ON CC:clang	28s
LuaJIT (Linux/x86_64) Debug GC64:OFF CC:gcc	34s
LuaJIT (Linux/x86_64) Debug GC64:OFF CC:clang	44s
LuaJIT (Linux/x86_64) Release GC64:ON CC:gcc	2m 22s
LuaJIT (Linux/x86_64) Release GC64:ON CC:clang	2m 39s
LuaJIT (macOS/x86_64) Release GC64:ON CC:clang	33s
LuaJIT (Linux/x86_64) Release GC64:OFF CC:gcc	32s
LuaJIT (Linux/x86_64) Release GC64:OFF CC:clang	33s
Tarantool (Linux/ARM64) Debug GC64:ON / luajit-integration	6m 26s
Tarantool (macOS/ARM64) Debug GC64:ON / luajit-integration	1m 34s
Tarantool (Linux/x86_64) Debug GC64:OFF / luajit-integration	2m 55s
Tarantool (Linux/ARM64) Release GC64:ON / luajit-integration	6m 36s
Tarantool (macOS/ARM64) Release GC64:ON / luajit-integration	1m 37s
Tarantool (Linux/x86_64) Debug GC64:ON / luajit-integration	4m 55s
Tarantool (macOS/x86_64) Debug GC64:ON / luajit-integration	2m 21s
Tarantool (Linux/x86_64) Release GC64:OFF / luajit-integration	2m 47s
Tarantool (Linux/x86_64) Release GC64:ON / luajit-integration	4m 1s
Tarantool (macOS/x86_64) Release GC64:ON / luajit-integration	2m 26s
	57m 51s

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