JVM: produce a better error on @JvmStatic external in interface

Java does not permit `static native` methods in interfaces, so this
never worked on any existing JRE.

 #KT-43696 Fixed

compiler/testData/diagnostics/testsWithStdLib/annotations/jvmStatic/interfaceCompanion_LL12.fir.kt

@@ -18,6 +18,8 @@ interface B {
 
         }
 
+        @JvmStatic external fun a5()
+
         @JvmStatic
         var foo = 1
 
@@ -49,6 +51,11 @@ interface B {
 
         public var foo9 = 1
         @JvmStatic private set
+
+        @JvmStatic
+        val foo10: Int external get
+
+        val foo11: Int @JvmStatic external get
     }
 
 }