`trmm` test failing on Kokkos impl

@mhoemmen @fnrizzi
With Kokkos implementations connected by #209, trmm native test fails when executed on Kokkos implementation (with LINALG_ENABLE_KOKKOS_DEFAULT=ON), e.g. see this CI job. There seem to be two issues:

1. Kokkos View crashing:

unknown file: Failure
C++ exception with description "Constructing View and initializing data with uninitialized execution space" thrown in the test body.

2. incorrect results:

[ RUN      ] BLAS3_trmm.left_lower_tri_implicit_diag
/home/runner/work/stdBLAS/stdBLAS/src/stdblas/tests/native/trmm.cpp:140: Failure
The difference between gs(i,j) and C(i,j) is nan, which exceeds tol, where
gs(i,j) evaluates to -4.4000000000000004,
C(i,j) evaluates to nan, and
tol evaluates to 1.0000000000000001e-09.
Matrices differ at index (0,0)

/home/runner/work/stdBLAS/stdBLAS/src/stdblas/tests/native/trmm.cpp:140: Failure
The difference between gs(i,j) and C(i,j) is nan, which exceeds tol, where
gs(i,j) evaluates to 7.4000000000000004,
C(i,j) evaluates to nan, and
tol evaluates to 1.0000000000000001e-09.
Matrices differ at index (1,0)

(...)

See full output: full-out.txt

Start with src/stdblas/tests/native/trmm.cpp and reproduce the native test with LINALG_ENABLE_KOKKOS_DEFAULT=ON, using the linked CI output and full-out.txt. Investigate the Kokkos View initialization exception and the NaN results in trmm. Done means the Kokkos-enabled trmm test runs without the exception and its matrix comparisons pass.