In BMv2, Translate architecture-dependent boolean parameter to JSON expression

[rupesh-chiluka-marvell]

Tried to solve the bug mentioned in the issue: #4985.

p4c/backends/bmv2/pna_nic/pnaNic.h

Lines 60 to 68 in b35c89b

	} else if (PnaProgramStructure::isStandardMetadata(ptName)) { // check if its pna metadata
	auto jsn = new Util::JsonObject();
	// encode the metadata type and field in json
	jsn->emplace("type"_cs, "field");
	auto a = mkArrayField(jsn, "value"_cs);
	a->append(ptName.exceptLast(2));
	a->append(fieldName);
	return jsn;

In the above code, If the parameter is part of architecture's standard metadata, it generates the JSON expression like:

"expression" : {
  "type" : "field",
  "value" : ["pna_main_input_metadata", "recirculated"]
}

Tried to tackle the case of a parameter being both architecture-dependent and a boolean.

[rupesh-chiluka-marvell]

Manually checked with both PSA and PNA example programs. Generated the JSON files as expected.