[llvm] [GISel][RISCV]Implement indirect parameter passing (PR #95429)

[Craig Topper via llvm-commits]

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@@ -16,6 +16,586 @@
 ; Check that on RV32, i64 is passed in a pair of registers. Unlike
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topperc wrote:

If possible I'd like to keep this testing in sync with the test files and naming from `llvm/test/CodeGen/RISCV/calling-conv-ilp32-ilp32f-ilp32d-common.ll`

https://github.com/llvm/llvm-project/pull/95429