Native: rename Xcode.current to .findCurrent()

To reflect that it is a non-trivial operation with possible performance
overhead.

kotlin-native/shared/src/main/kotlin/org/jetbrains/kotlin/konan/target/Apple.kt

@@ -55,7 +55,7 @@ class AppleConfigurablesImpl(
         if (InternalServer.isAvailable) {
             XcodePartsProvider.InternalServer
         } else {
-            val xcode = Xcode.current
+            val xcode = Xcode.findCurrent()
 
             if (properties.getProperty("ignoreXcodeVersionCheck") != "true") {
                 properties.getProperty("minimalXcodeVersion")?.let { minimalXcodeVersion ->

kotlin-native/shared/src/main/kotlin/org/jetbrains/kotlin/konan/target/Xcode.kt

@@ -56,8 +56,11 @@ interface Xcode {
     companion object {
         // Don't cache the instance: the compiler might be executed in a Gradle daemon process,
         // so current Xcode might actually change between different invocations.
+        @Deprecated("", ReplaceWith("this.findCurrent()"), DeprecationLevel.WARNING)
         val current: Xcode
-            get() = CurrentXcode()
+            get() = findCurrent()
+
+        fun findCurrent(): Xcode = CurrentXcode()
     }
 }