Use explicit types in LLVM Loads

[alexbaden]

In preparation for switching to opaque pointers, remove pointer type accesses from various loads.

[alexbaden]

Windows failure is the same old reloc one:

2023-08-29T20:18:12.3501189Z   17: Test command: D:\a\hdk\hdk\build\omniscidb\Tests\Release\NoCatalogSqlTest.exe "--gtest_output=xml:../"
2023-08-29T20:18:12.3502027Z   17: Working Directory: D:/a/hdk/hdk/build/omniscidb/Tests
2023-08-29T20:18:12.3502600Z   17: Test timeout computed to be: 10000000
2023-08-29T20:18:12.5638518Z   17: [==========] Running 7 tests from 2 test suites.
2023-08-29T20:18:12.5639782Z   17: [----------] Global test environment set-up.
2023-08-29T20:18:12.5640615Z   17: [----------] 5 tests from NoCatalogSqlTest
2023-08-29T20:18:12.5863584Z   17: [ RUN      ] NoCatalogSqlTest.SelectSingleColumn
2023-08-29T20:18:16.3293732Z   17: [       OK ] NoCatalogSqlTest.SelectSingleColumn (3708 ms)
2023-08-29T20:18:16.3295300Z   17: [ RUN      ] NoCatalogSqlTest.SelectAllColumns
2023-08-29T20:18:16.3666987Z   17: [       OK ] NoCatalogSqlTest.SelectAllColumns (70 ms)
2023-08-29T20:18:16.3667998Z   17: [ RUN      ] NoCatalogSqlTest.SelectAllColumnsMultiFrag
2023-08-29T20:18:17.3852297Z 17 : LLVM error : IMAGE_REL_AMD64_ADDR32NB relocation requires an ordered section layout [D:\a\hdk\hdk\build\omniscidb\Tests\sanity_tests.vcxproj]
2023-08-29T20:18:17.3853427Z   13/17 Test #17: NoCatalogSqlTest .................***Failed    4.10 sec

and can be ignored.