[clang][RISCV][test] Add more tests of the -mabi and -march options

1. There is no tests for mabi=ilp32e, and my patch covers that.
2. The tests in riscv-abi.c will show default ABI changes for special archs
   in the future, especially the arch with the F but without the D extension.
3. The tests in riscv-arch.c will show default arch changes for abi=ilp32,
   which is rv32imacfd currently, but it is better to be rv32imac.
   And it is also better for abi=ilp32f defaults to arch=imacf.

Reviewed By: MaskRay, luismarques

Differential Revision: https://reviews.llvm.org/D103878