LuaJIT 2.1_p20260724 test failure on Alpine ppc64le

Test failure when bumping the Alpine package:

eg: https://gitlab.alpinelinux.org/huajingyun01/aports/-/jobs/2505386#L376

Partial error logs are as follows:

Failed test when running /builds/huajingyun01/aports/main/luajit/src/luajit2-2.1-20260724/test-suite/target/bin/luajit-2.1.1784881202 fwd_hrefk_rollback.lua 1: 256
=== test/misc/hstore_elimination.lua
=== test/misc/bit_op.lua
/builds/huajingyun01/aports/main/luajit/src/luajit2-2.1-20260724/test-suite/target/bin/luajit-2.1.1784881202: bit.tobit test failed (got 140, expected 277312)
stack traceback:
	[C]: in function 'error'
	bit_op.lua:15: in function 'cksum'
	bit_op.lua:26: in function 'check_unop'
	bit_op.lua:70: in main chunk
	[C]: at 0x01002b5d70
Failed test when running /builds/huajingyun01/aports/main/luajit/src/luajit2-2.1-20260724/test-suite/target/bin/luajit-2.1.1784881202 bit_op.lua 1: 256
=== test/misc/table_misc.lua
/builds/huajingyun01/aports/main/luajit/src/luajit2-2.1-20260724/test-suite/target/bin/luajit-2.1.1784881202: table_misc.lua:41: assertion failed!
stack traceback:
	[C]: in function 'assert'
	table_misc.lua:41: in main chunk
	[C]: at 0x0126d55d70
Failed test when running /builds/huajingyun01/aports/main/luajit/src/luajit2-2.1-20260724/test-suite/target/bin/luajit-2.1.1784881202 table_misc.lua 1: 256
=== test/misc/api_call.lua
=== test/misc/vararg_jit.lua
=== test/misc/tcall_base.lua
=== test/misc/debug_gc.lua
ERROR in finalizer: debug_gc.lua:13: attempt to index local 'dbg' (a nil value)
/builds/huajingyun01/aports/main/luajit/src/luajit2-2.1-20260724/test-suite/target/bin/luajit-2.1.1784881202: debug_gc.lua:42: __gc metamethod not called

Start by reproducing the Alpine ppc64le failure from the linked job and inspect the LuaJIT test-suite results. Focus on bit_op.lua, table_misc.lua, debug_gc.lua, and fwd_hrefk_rollback.lua; done means identifying and fixing the architecture-specific cause so the reported tests pass.