NXP backend: Fix `mean.dim` delegation and tests.#14581

MartinPavella merged 1 commit intopytorch:mainpytorch/executorch:mainfrom

nxp-upstream:upstream/main-nxp/EIEX-522-fix-mean.dim-delegation-and-testsnxp-upstream/executorch:upstream/main-nxp/EIEX-522-fix-mean.dim-delegation-and-testsCopy head branch name to clipboard