Fix Meta(pattern=..) memory leak / corruption - #1256

 ==2637==ERROR: AddressSanitizer: attempting free on address which was not malloc()-ed: 0x50e000e8e350 in thread T0
    #0 0x7f07a10fc4d8 in free ../../../../src/libsanitizer/asan/asan_malloc_linux.cpp:52
    #1 0x7f079c42ddf4 in TypeNode_Free src/msgspec/_core.c:3474
    #2 0x7f079c42dbdf in TypeNode_Free src/msgspec/_core.c:3468
    #3 0x7f079c55e2eb in JSONDecoder_dealloc src/msgspec/_core.c:17235
    #4 0x7f07a0999132 in _PyEval_EvalFrameDefault Python/bytecodes.c:1398
    #5 0x7f07a0a15f73 in _PyObject_VectorcallTstate Include/internal/pycore_call.h:92
    #6 0x7f07a0a15f73 in method_vectorcall Objects/classobject.c:69
    #7 0x7f07a098d82f in _PyEval_EvalFrameDefault Python/bytecodes.c:3263
    #8 0x7f07a0a14e6c in _PyFunction_Vectorcall Objects/call.c:419
    #9 0x7f07a0a14e6c in _PyObject_FastCallDictTstate Objects/call.c:144
    #10 0x7f07a0a14e6c in _PyObject_Call_Prepend Objects/call.c:508
    #11 0x7f07a0ac3381 in slot_tp_call Objects/typeobject.c:8791
    #12 0x7f07a0a14206 in _PyObject_MakeTpCall Objects/call.c:240
    #13 0x7f07a098d20a in _PyEval_EvalFrameDefault Python/bytecodes.c:2715
    #14 0x7f07a0a14e6c in _PyFunction_Vectorcall Objects/call.c:419
    #15 0x7f07a0a14e6c in _PyObject_FastCallDictTstate Objects/call.c:144
    #16 0x7f07a0a14e6c in _PyObject_Call_Prepend Objects/call.c:508
    #17 0x7f07a0ac3381 in slot_tp_call Objects/typeobject.c:8791
    #18 0x7f07a0a1550e in PyObject_Call (/opt/hostedtoolcache/Python/3.12.15/x64/lib/libpython3.12.so.1.0+0x21550e) (BuildId: d5ce433e66c26342bfaf6b82ab1a95541a8ebade)
    #19 0x7f07a098d82f in _PyEval_EvalFrameDefault Python/bytecodes.c:3263
    #20 0x7f07a0a14e6c in _PyFunction_Vectorcall Objects/call.c:419
    #21 0x7f07a0a14e6c in _PyObject_FastCallDictTstate Objects/call.c:144
    #22 0x7f07a0a14e6c in _PyObject_Call_Prepend Objects/call.c:508
    #23 0x7f07a0ac3381 in slot_tp_call Objects/typeobject.c:8791
    #24 0x7f07a0a14206 in _PyObject_MakeTpCall Objects/call.c:240
    #25 0x7f07a098d20a in _PyEval_EvalFrameDefault Python/bytecodes.c:2715
    #26 0x7f07a0a14e6c in _PyFunction_Vectorcall Objects/call.c:419
    #27 0x7f07a0a14e6c in _PyObject_FastCallDictTstate Objects/call.c:144
    #28 0x7f07a0a14e6c in _PyObject_Call_Prepend Objects/call.c:508
    #29 0x7f07a0ac3381 in slot_tp_call Objects/typeobject.c:8791
    #30 0x7f07a0a14206 in _PyObject_MakeTpCall Objects/call.c:240
    #31 0x7f07a098d20a in _PyEval_EvalFrameDefault Python/bytecodes.c:2715
    #32 0x7f07a0a14e6c in _PyFunction_Vectorcall Objects/call.c:419
    #33 0x7f07a0a14e6c in _PyObject_FastCallDictTstate Objects/call.c:144
    #34 0x7f07a0a14e6c in _PyObject_Call_Prepend Objects/call.c:508
    #35 0x7f07a0ac3381 in slot_tp_call Objects/typeobject.c:8791
    #36 0x7f07a0a14206 in _PyObject_MakeTpCall Objects/call.c:240
    #37 0x7f07a098d20a in _PyEval_EvalFrameDefault Python/bytecodes.c:2715
    #38 0x7f07a0ae8f35 in PyEval_EvalCode Python/ceval.c:580
    #39 0x7f07a0ae7a3c in builtin_exec_impl Python/bltinmodule.c:1093
    #40 0x7f07a0ae7a3c in builtin_exec Python/clinic/bltinmodule.c.h:543
    #41 0x7f07a0a345a2 in cfunction_vectorcall_FASTCALL_KEYWORDS Objects/methodobject.c:438
    #42 0x7f07a0a14532 in _PyObject_VectorcallTstate Include/internal/pycore_call.h:92
    #43 0x7f07a0a14532 in PyObject_Vectorcall Objects/call.c:325
    #44 0x7f07a098d20a in _PyEval_EvalFrameDefault Python/bytecodes.c:2715
    #45 0x7f07a0ae8f35 in PyEval_EvalCode Python/ceval.c:580
    #46 0x7f07a0b09f76 in run_eval_code_obj Python/pythonrun.c:1757
    #47 0x7f07a0b09aaa in run_mod Python/pythonrun.c:1778
    #48 0x7f07a0b099f1 in pyrun_file Python/pythonrun.c:1674
    #49 0x7f07a0b09852 in _PyRun_SimpleFileObject Python/pythonrun.c:459
    #50 0x7f07a0b09667 in _PyRun_AnyFileObject Python/pythonrun.c:78
    #51 0x7f07a0b12943 in pymain_run_file_obj Modules/main.c:361
    #52 0x7f07a0b12943 in pymain_run_file Modules/main.c:380
    #53 0x7f07a0b12943 in pymain_run_python Modules/main.c:634
    #54 0x7f07a0b12943 in Py_RunMain Modules/main.c:714
    #55 0x7f07a0b1243a in Py_BytesMain Modules/main.c:768
    #56 0x7f07a042a1c9  (/lib/x86_64-linux-gnu/libc.so.6+0x2a1c9) (BuildId: a4a7992a8e66555c8141ab2a08a8465ff6e0ea65)
    #57 0x7f07a042a28a in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2a28a) (BuildId: a4a7992a8e66555c8141ab2a08a8465ff6e0ea65)
    #58 0x558976af7094 in _start (/opt/hostedtoolcache/Python/3.12.15/x64/bin/python3.12+0x1094) (BuildId: d664fd041bd9df9902c326eb80717fa04325aaaa)

0x50e000e8e350 is located 16 bytes inside of 152-byte region [0x50e000e8e340,0x50e000e8e3d8)
allocated by thread T0 here:
    #0 0x7f07a10fd9c7 in malloc ../../../../src/libsanitizer/asan/asan_malloc_linux.cpp:69
    #1 0x7f07a0a7c2fc in gc_alloc Modules/gcmodule.c:2330
    #2 0x7f07a0a7c2fc in _PyObject_GC_NewVar Modules/gcmodule.c:2364

SUMMARY: AddressSanitizer: bad-free ../../../../src/libsanitizer/asan/asan_malloc_linux.cpp:52 in free
==2637==ABORTING