Fix indexing of solsym in run_chm_diags_ts_355 test.

[overfelt]

In the unit test validate_chm_diags_ts_355 defined in file validation/mo_chm_diags/chm_diags.cpp the names of gas-phase chemical constituents array is dimensioned as char solsym[gas_pcnst][17] where constexpr const int gas_pcnst = gas_chemistry::gas_pcnst; which is 31 but in the mo_chm_diags::chm_diags function that is being tested is indexed in a loop of the form for (int nn = lchnk; nn < pcnst; nn++) where pcnst is set in the file mo_chm_diags.hpp as

 27 constexpr const int pcnst = 80; // FIXME, 80 is the only value I found for this
 28                                 // in the fortran, but using 41 in the test  

Also the setting of char solsym[gas_pcnst][17] is not correct. This is set to an array of char * so should be char *solsym[gas_pcnst].