Remove the Identifier::is() method. NFC.

[lattner]

Summary

Depends on D78042.

[rriddle]

nit: Can you add a little context/justification in the description?

[lattner]

Sure, no problem. Thanks!

mlir/include/mlir/IR/Identifier.h

public:
   const char *c_str() const { return entry->getKeyData(); }
 
   /// Return a pointer to the start of the string data.
   const char *data() const { return entry->getKeyData(); }
 
   /// Return the number of bytes in this string.
   unsigned size() const { return entry->getKeyLength(); }
 
-  /// Return true if this identifier is the specified string.
-  bool is(StringRef string) const { return strref() == string; }
-
   const char *begin() const { return data(); }
   const char *end() const { return entry->getKeyData() + size(); }
 
   bool operator==(Identifier other) const { return entry == other.entry; }
   bool operator!=(Identifier rhs) const { return !(*this == rhs); }
 
   void print(raw_ostream &os) const;
   void dump() const;