[K/N] Separate ClangArgs for jni and native

Since LLVM for Windows is now native instead on MinGW, we have to
compile code in a different environment in case of JNI. This commits
just separates ClangArgs into two subclasses without actual behavior
changes.

kotlin-native/Interop/Runtime/build.gradle.kts

@@ -35,10 +35,10 @@ native {
     val host = rootProject.project(":kotlin-native").extra["hostName"]
     val hostLibffiDir = rootProject.project(":kotlin-native").extra["${host}LibffiDir"]
     val cflags = mutableListOf("-I$hostLibffiDir/include",
-                               *platformManager.hostPlatform.clang.hostCompilerArgsForJni)
+                               *platformManager.hostPlatform.clangForJni.hostCompilerArgsForJni)
     suffixes {
         (".c" to ".$obj") {
-            tool(*platformManager.hostPlatform.clang.clangC("").toTypedArray())
+            tool(*platformManager.hostPlatform.clangForJni.clangC("").toTypedArray())
             flags( *cflags.toTypedArray(), "-c", "-o", ruleOut(), ruleInFirst())
         }
     }
@@ -50,7 +50,7 @@ native {
     val objSet = sourceSets["callbacks"]!!.transform(".c" to ".$obj")
 
     target(solib("callbacks"), objSet) {
-        tool(*platformManager.hostPlatform.clang.clangCXX("").toTypedArray())
+        tool(*platformManager.hostPlatform.clangForJni.clangCXX("").toTypedArray())
         flags("-shared",
               "-o",ruleOut(), *ruleInAll(),
               "-L${project(":kotlin-native:libclangext").buildDir}",