test_horiz_interp: Don't over-allocate arrays

[J-Lentz]

Description
In the horiz_interp_type assignment 1x2d bicubic test, there are four allocatable arrays for which the number of elements allocated exceeds the number that get initialized:

• lon_src_1d
• lat_src_1d
• lon_out_1d
• lat_out_1d

This PR shortens the sizes of the arrays to match the number of elements that get initialized.

Fixes horiz_interp tests 23-24 with ifort using strict debug flags. It also fixes the tests with the Cray compiler. I'm requesting a careful review from @rem1776, because while this change does make the tests pass, I'm not sure whether or not the over-allocation may be a deliberate part of the test.

How Has This Been Tested?
horiz_interp tests build, run, and pass with CCE 18 on C5 and with ifort using the following debug flags:

-check all -fpe0 -fp-stack-check -fstack-security-check -ftrapuv -init=arrays,minus_huge,snan

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• Any dependent changes have been merged and published in downstream modules
• New check tests, if applicable, are included
• make distcheck passes

[rem1776]

@J-Lentz Yeah this wasn't intentional, not sure why exactly they have one extra index. Thanks for the fix!