Fix memleak in x86.nz asm plugin #18121

Job	Run time
changes	5s
Build on CentOS 7	0s
Build on old Debian ${{ matrix.container }}	0s
Build on gcc 11 ASAN	0s
Build static	0s
Create source tarball	0s
Run debug tests on Ubuntu 20.04	0s
Test source tarball	0s
Build rizin rzpipe	0s
Build rz-bindgen	0s
linux-meson-clang-tests	1s
linux-meson-gcc-tests	23m 7s
macos-meson-clang-tests	13m 44s
linux-gcc-tests-asan	1h 13m 44s
linux-clang-tests-asan	59m 35s
linux-gcc-tests-codecov	2s
capstone-v4	1s
capstone-v5	2s
capstone-sys	1s
no-gpl-code	1s
Publish Docker image on Docker Hub	0s
Build Android ${{ matrix.name }} package	0s
Build Windows zip/installer ${{ matrix.name }}	0s
Test EXTRA_PREFIX works well	0s
Include Rizin headers from C++ program (Linux)	0s
Build OSX package	0s
Test Windows installer built with ${{ matrix.name }}	0s
Test OSX pkg	0s
Create draft release and upload artifacts	0s
	2h 50m 23s

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