[CMake][OpenMP] Remove wrong backslash

outdir is defined in the line above, it will not exist in the install
command, so it should not be escaped.

GitOrigin-RevId: 50716ba2b337afe46ac256cc91673dc27356a776
diff --git a/runtime/src/CMakeLists.txt b/runtime/src/CMakeLists.txt
index 02f65aa..9bc8837 100644
--- a/runtime/src/CMakeLists.txt
+++ b/runtime/src/CMakeLists.txt
@@ -380,7 +380,7 @@
       extend_path(outdir "${CMAKE_INSTALL_PREFIX}" "${OPENMP_INSTALL_LIBDIR}")
       install(CODE "execute_process(COMMAND \"\${CMAKE_COMMAND}\" -E create_symlink \"${LIBOMP_LIB_FILE}\"
         \"${alias}${LIBOMP_LIBRARY_SUFFIX}\" WORKING_DIRECTORY
-        \"\$ENV{DESTDIR}\${outdir}\")")
+        \"\$ENV{DESTDIR}${outdir}\")")
     endforeach()
   endif()
 endif()