[build][version] more accurate version string for local builds (drops -1 in build number)

shared/buildSrc/src/main/kotlin/org/jetbrains/kotlin/VersionGenerator.kt

@@ -52,8 +52,10 @@ open class VersionGenerator: DefaultTask() {
                      |       }
                      |       append('-')
                      |       append(meta.metaString)
-                     |       append('-')
+                     |       if (build != -1) {
-                     |       append(build)
+                     |         append('-')
+                     |         append(build)
+                     |       }
                      |     }
                      |  }
                      |  override fun toString() = versionString