[Compiler] Add more tests for non-power-of-two primitive types (#58437)
The issue reported in #42326 (inconsistent sizes for structs involving
primitive types with non-power-of-two sizes) is already fixed since
upgrading to LLVM 18, this PR adds regressions tests. I verified they
already pass on x86_64, i686 and aarch64.
Close #42326.