Support variadic ops in declarative rewrite rules

This CL extends declarative rewrite rules to support matching and
generating ops with variadic operands/results. For this, the
generated `matchAndRewrite()` method for each pattern now are
changed to

* Use "range" types for the local variables used to store captured
  values (`operand_range` for operands, `ArrayRef<Value *>` for
  values, *Op for results). This allows us to have a unified way
  of handling both single values and value ranges.
* Create local variables for each operand for op creation. If the
  operand is variadic, then a `SmallVector<Value*>` will be created
  to collect all values for that operand; otherwise a `Value*` will
  be created.
* Use a collective result type builder. All result types are
  specified via a single parameter to the builder.

We can use one result pattern to replace multiple results of the
matched root op. When that happens, it will require specifying
types for multiple results. Add a new collective-type builder.

PiperOrigin-RevId: 264588559