Port "sub-group transpose reduction" to default path

[victor-eds]

#2109 explores layout conversion in the advanced path to improve reduction performance (see #1637 for investigation). Porting this to the default path would involve a transformation similar to (after heuristics to check profitability):

1. Reshape input tensor so no data movement is needed and we can perform reduction of elements within the work-item tt.reshape
2. Perform reduction within the work-item tt.reduce
3. Convert layout so a transposition within the sub-group as explained in the investigation is performed triton_gpu.convert_layout
4. Finalize reduction (within work-item and possibly within the work-group) tt.reduce
5. Convert back to initial layout triton_gpu.convert_layout

Note 5 can be dropped in case the new layout is beneficial for performance.

[victor-eds]

Working on generating always NOP reshape ops.

[victor-eds]

Adding lit tests locally. Pass 1.0 in a good shape.

[victor-eds]

Pass working for repCluster[0] = 2 case. Working on repCluster[0] > 2 (real cases). Pass itself working fine with it (finalizing tests), will work on layout conversion optimizations too.