Advance buildKotlinVersion to 1.4.0-dev-9619
Advance buildKotlinVersion to 1.4.0-dev-9619

Use it to build shared tools.
Earlier, kotlinVersion was used, which caused shared and main project
being built with different versions of the compiler.

(cherry picked from commit d4ffca9800b40256cf9d505911ca8c8f7acadc4d)

wiltonlazary/kotlin-native,JetBrains/kotlin-native,JetBrains/kotlin-native,JetBrains/kotlin-native,wiltonlazary/kotlin-native,JetBrains/kotlin-native,wiltonlazary/kotlin-native,wiltonlazary/kotlin-native,wiltonlazary/kotlin-native,JetBrains/kotlin-native,JetBrains/kotlin-native,JetBrains/kotlin-native,JetBrains/kotlin-native,JetBrains/kotlin-native