remove unnecessary environment variable (#19166)

remove unnecessary environment variable when building as arm64x

build_arm64x.bat

@@ -5,7 +5,6 @@
 
 setlocal
 set PATH=C:\Program Files\Git\usr\bin;%PATH%
-set LINK_REPRO_NAME=/mylink.rsp
 
 rem Requires a Python install to be available in your PATH
 python "%~dp0\tools\ci_build\build.py" --arm64 --buildasx  --build_dir "%~dp0\build\arm64-x" %*