[CodeGen][AMDGPU] Remove premature empty subrange elimination (#201263)
This commit removes a call to `removeEmptySubRanges` inside
`SplitEditor::rewriteAssigned` which removes empty subranges that may be
expected at a later stage. The empty subranges are eliminated by a later
call to `removeEmptySubRanges`.
Fixes https://github.com/llvm/llvm-project/issues/199337.
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Signed-off-by: Steffen Holst Larsen <sholstla@amd.com>