Don't always write JVM method signatures to metadata

When the trivial type mapping (implemented in JvmProtoBufUtil) from
ProtoBuf.Type instances works fine, don't write the signature since it can be
loaded by exactly the same trivial type mapping

Original commit: 864926ee2e

jps/jps-plugin/src/org/jetbrains/kotlin/jps/incremental/ProtoCompareGenerated.kt

@@ -330,9 +330,15 @@ open class ProtoCompareGenerated(public val oldNameResolver: NameResolver, publi
     }
 
     open fun checkEquals(old: JvmProtoBuf.JvmMethodSignature, new: JvmProtoBuf.JvmMethodSignature): Boolean {
-        if (!checkStringEquals(old.name, new.name)) return false
+        if (old.hasName() != new.hasName()) return false
+        if (old.hasName()) {
+            if (!checkStringEquals(old.name, new.name)) return false
+        }
 
-        if (!checkStringEquals(old.desc, new.desc)) return false
+        if (old.hasDesc() != new.hasDesc()) return false
+        if (old.hasDesc()) {
+            if (!checkStringEquals(old.desc, new.desc)) return false
+        }
 
         return true
     }
@@ -896,9 +902,13 @@ public fun ProtoBuf.ValueParameter.hashCode(stringIndexes: (Int) -> Int, fqNameI
 public fun JvmProtoBuf.JvmMethodSignature.hashCode(stringIndexes: (Int) -> Int, fqNameIndexes: (Int) -> Int): Int {
     var hashCode = 1
 
-    hashCode = 31 * hashCode + stringIndexes(name)
+    if (hasName()) {
+        hashCode = 31 * hashCode + stringIndexes(name)
+    }
 
-    hashCode = 31 * hashCode + stringIndexes(desc)
+    if (hasDesc()) {
+        hashCode = 31 * hashCode + stringIndexes(desc)
+    }
 
     return hashCode
 }