[RISCV] Reorder masked builtin operands. Use clang_builtin_alias for all...

[RISCV] Reorder masked builtin operands. Use clang_builtin_alias for all overloaded vector builtins.

This patch makes the builtin operand order match the C operand order
for all intrinsics. With this we can use clang_builtin_alias for
all overloaded intrinsics.

This should further reduce the test time for vector intrinsics.

Differential Revision: https://reviews.llvm.org/D101700