Update the built-in signatures in BuiltinsLoongArchLSX.def and
BuiltinsLoongArchLASX.def to precisely match the vector types used in
the corresponding intrinsic headers (lsxintrin.h and lasxintrin.h).
This alignment ensures that these intrinsics can be compiled
successfully even when -flax-vector-conversions=none is specified, since
the built-in arguments no longer rely on implicit vector type
conversions.
Added new test cases to verify the macro-defined LSX/LASX
intrinsic interfaces under -flax-vector-conversions=none.
Fixes#189898
76fc936175