Clang computes the default ABI if -mabi is empty
and encode it in LLVM IR module flag since D105555.
For correctness, llc need to give the same target-abi
(Options.MCOptions.ABIName) with ABI encoded in IR.
The getSubtargetImpl already has a check for them only if
Options.MCOptions.ABIName is not empty.
In order to get more robustness we could have a check for
explicit ABI, but now we have two different logic to
compute the default ABI.
The front-end ABI is defautl to the ilp32/ilp32e/lp64, and
ilp32d/lp64d when hardware support for extension D.
The backend ABI is default to the ilp32/ilp32e/lp64.
Due to the default target-abi for llc had changed, I update
some tests by specific the target-abi with old default value
to make the expected result unchanged.
For a bunch of these it seems it'd make more sense to just use a hard-float ABI. I think it's worthwhile keeping this as NFC test-wise, but don't know if it makes sense to update the ABIs first and make this patch smaller or land this then go through at a later date so as to not stall this patch.