This patch adds support for specifying all target memory locations using
a
single IR spellings such as:
```
memory(target_mem: read)
```
This form is not supported in TableGen, but it is now accepted by the IR
parser.
When the parser encounters target_mem, it expands it to all
target-memory
locations (e.g., target_mem0, target_mem1, …).
Printing behavior
When all target-memory locations share the same ModRef value, the
printer
now collapses them into a single entry:
```
memory(target_mem: read)
```
Otherwise, each target memory location is printed separately.
Rejected IR:
```
memory(target_mem0: write, target_mem: read)
```
This is invalid because the default access kind for the target memory
group
must appear first.
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