jitstressregs failures after multireg changes

[sandreenko]

JIT\Directed\StructABI\StructABI\StructABI.cmd with jitstressregs=4 started to fail after #36155 with

!"Invalid node type for GetRegTypeByIndex"' in 'ILStubClass:IL_STUB_PInvoke(SingleLong):SingleLong' during 'Generate code' (IL size 53)

    File: F:\git\runtime\src\coreclr\src\jit\gentree.h Line: 7307

then the assert changed to Failed after #36802:

Native call for EchoSingleLong failed
Native call for EchoSingleByte failed
Native call for EchoSingleDouble failed
Native call for EchoSingleDouble failed
Native call for EchoByteAndFloat failed
Native call for EchoByteAndFloat failed
Native call for EchoPointerAndByte failed
Native call for EchoByteAndPointer failed
Native call for EchoTwoFloats failed
Native call for EchoInlineArray6 failed
Expected: 100
Actual: -1
END EXECUTION - FAILED
FAILED

There are many tests on non-Win platforms that are still failing with asserts, see jitstressregs job