This patch introduces bitcode reader/writer support for the optional ptr_provenance operand of load/store instructions.
This is done in a backwards and future compatible way: when present, an extra 'bool true' + the value and type are pushed.
When reading, if there are extra values, the first bool indicates if a ptr_provenance operand is available or not.
If in future more optional values are needed, extra bools can be added to indicate that they are present. As soon as one extra
optional value is emitted, the status of the others should also be emitted.
Note: this corresponds to D87254