`norm2` test failing on Kokkos impl

@mhoemmen @fnrizzi
norm2 native test fails when executed on Kokkos implementation (with LINALG_ENABLE_KOKKOS_DEFAULT=ON), e.g. see this CI job:

      Start 14: norm2
15/36 Test #14: norm2 ................................***Failed    0.01 sec
Running main() from /home/runner/work/stdBLAS/stdBLAS/build/stdblas/_deps/googletest-src/googletest/src/gtest_main.cc
[==========] Running 4 tests from 1 test suite.
[----------] Global test environment set-up.
[----------] 4 tests from BLAS1_norm2
[ RUN      ] BLAS1_norm2.mdspan_zero
[       OK ] BLAS1_norm2.mdspan_zero (0 ms)
[ RUN      ] BLAS1_norm2.mdspan_one
/home/runner/work/stdBLAS/stdBLAS/src/stdblas/tests/native/norm2.cpp:85: Failure
Expected equality of these values:
  expectedNormResult + mag_t(1.0)
    Which is: 4
  normResultPlusOne
    Which is: 3.16228
[  FAILED  ] BLAS1_norm2.mdspan_one (0 ms)
[ RUN      ] BLAS1_norm2.mdspan_double
[       OK ] BLAS1_norm2.mdspan_double (0 ms)
[ RUN      ] BLAS1_norm2.mdspan_complex_double
[       OK ] BLAS1_norm2.mdspan_complex_double (0 ms)
[----------] 4 tests from BLAS1_norm2 (0 ms total)

[----------] Global test environment tear-down
[==========] 4 tests from 1 test suite ran. (0 ms total)
[  PASSED  ] 3 tests.
[  FAILED  ] 1 test, listed below:
[  FAILED  ] BLAS1_norm2.mdspan_one

 1 FAILED TEST

Start with src/stdblas/tests/native/norm2.cpp, especially the failing assertion at line 85, and compare the native norm2 behavior with the Kokkos implementation using LINALG_ENABLE_KOKKOS_DEFAULT=ON. Re-run the norm2 test or the linked CI job; done means BLAS1_norm2.mdspan_one and the complete norm2 test pass under the Kokkos implementation.