Remove unused variable

src/google/protobuf/compiler/java/java_helpers.cc

@@ -90,17 +90,6 @@ const std::unordered_set<std::string>* kReservedNames =
         "transient",  "try",          "void",      "volatile",   "while",
     });
 
-// Names that should be avoided as field names in Kotlin.
-// All Kotlin hard keywords are in this list.
-const std::unordered_set<std::string>* kKotlinForbiddenNames =
-    new std::unordered_set<std::string>({
-        "as",    "as?",   "break", "class",  "continue",  "do",     "else",
-        "false", "for",   "fun",   "if",     "in",        "!in",    "interface",
-        "is",    "!is",   "null",  "object", "package",   "return", "super",
-        "this",  "throw", "true",  "try",    "typealias", "typeof", "val",
-        "var",   "when",  "while",
-    });
-
 bool IsForbidden(const std::string& field_name) {
   for (int i = 0; i < GOOGLE_ARRAYSIZE(kForbiddenWordList); ++i) {
     if (field_name == kForbiddenWordList[i]) {