Refactor deprecation by version requirement

- Get rid of ApiVersion in favor of MavenComparableVersion
- Don't crash on invalid versions in RequireKotlin
- Extract to a separate function

compiler/util/src/org/jetbrains/kotlin/config/ApiVersion.kt

@@ -16,7 +16,6 @@
 
 package org.jetbrains.kotlin.config
 
-import org.jetbrains.kotlin.serialization.deserialization.descriptors.VersionRequirement
 import org.jetbrains.kotlin.utils.DescriptionAware
 
 class ApiVersion private constructor(
@@ -59,10 +58,6 @@ class ApiVersion private constructor(
         @JvmStatic
         fun createByLanguageVersion(version: LanguageVersion): ApiVersion = parse(version.versionString)!!
 
-        @JvmStatic
-        fun createByVersionRequirement(versionRequirement: VersionRequirement): ApiVersion =
-                versionRequirement.version.let { version -> parse(version.asString()) ?: error("Could not parse version: $version") }
-
         fun parse(versionString: String): ApiVersion? = try {
             ApiVersion(MavenComparableVersion(versionString), versionString)
         }