Drop the 8 Extent0..4 / Stride0..3 cases from the shared FlyROCDL
AtomStateField enum. Their struct slots are unchanged; CopyOpGFX1250TDMType
now resolves the "extent_i" / "stride_i" field names locally (tdmGeomSlot)
instead of via symbolizeAtomStateField, so fly.atom.set_value still accepts
them but they no longer pollute the cross-atom vocabulary.

make_tdm_atom's signature/behavior and all call sites (incl. aiter) are
unchanged; getConvertedType and the descriptor struct layout are identical
(mask=0, extent 1..5, stride 6..9, imm_offset=10). WorkgroupMask/ImmOffset
stay in the shared enum.

Verified: tdm_gfx1250.mlir FileCheck + test_gfx1250_atoms.py round-trip pass.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>