Revert "Rename Extension annotation to ExtensionFunctionType"

This reverts commit 460dad135c.

The old compiler will not see the new runtime correctly. Postponing this until
1.0

idea/testData/decompiler/decompiledText/FunctionTypes.expected.kt

@@ -10,7 +10,7 @@ public final class FunctionTypes public constructor() {
 
     public final fun f3(f: kotlin.Int.(kotlin.Int) -> kotlin.Unit): kotlin.Unit { /* compiled code */ }
 
-    public final fun f4(f: kotlin.List<@kotlin.ExtensionFunctionType kotlin.Function1<*, *>>): kotlin.Unit { /* compiled code */ }
+    public final fun f4(f: kotlin.List<@kotlin.Extension kotlin.Function1<*, *>>): kotlin.Unit { /* compiled code */ }
 
     public final fun <A> (A.(A) -> A)?.bar(): kotlin.Unit { /* compiled code */ }
 
@@ -19,4 +19,4 @@ public final class FunctionTypes public constructor() {
     public final fun <IP, R, P1> ((IP) -> R).compose2(f: (P1) -> IP): (P1) -> R { /* compiled code */ }
 
     public final fun <A> (A.(A) -> A).foo(): kotlin.Unit { /* compiled code */ }
-}
+}

idea/testData/decompiler/decompiledText/FunctionTypes/FunctionTypes.kt

@@ -21,9 +21,9 @@ class FunctionTypes {
     public fun f2(f: Function2<Int, *, String>) {
     }
 
-    public fun f3(f: @ExtensionFunctionType Function2<Int, Int, Unit>) {
+    public fun f3(f: @Extension Function2<Int, Int, Unit>) {
     }
 
-    public fun f4(f: List<@ExtensionFunctionType Function1<*, *>>) {
+    public fun f4(f: List<@Extension Function1<*, *>>) {
     }
 }