[mlir][EmitC] Expand the MemRefToEmitC pass - Lowering CopyOp (#151206)
This patch lowers `memref.copy` to `emitc.call_opaque "memcpy"`.
From:
```
func.func @copying(%arg0 : memref<9x4x5x7xf32>, %arg1 : memref<9x4x5x7xf32>) {
memref.copy %arg0, %arg1 : memref<9x4x5x7xf32> to memref<9x4x5x7xf32>
return
}
```
To:
```cpp
#include <cstring>
void copying(float v1[9][4][5][7], float v2[9][4][5][7]) {
size_t v3 = 0;
float* v4 = &v2[v3][v3][v3][v3];
float* v5 = &v1[v3][v3][v3][v3];
size_t v6 = sizeof(float);
size_t v7 = 1260;
size_t v8 = v6 * v7;
memcpy(v5, v4, v8);
return;
}
```
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