Add MutableMap.remove(K, V) as built-in declaration

Use PlatformDependent annotation to guarantee it's only be available for JDK8
Also adjust type-safe bridges and mutable collection stubs generation

compiler/testData/loadJava8/compiledJava/MapRemove.java

@@ -0,0 +1,15 @@
+package test;
+import java.util.Map;
+public class MapRemove {
+    public abstract class MyMap<K, V> implements Map<K, V> {
+        public boolean remove(Object x, Object y) { return false; }
+    }
+
+    public abstract class MyMapString implements Map<String, Integer> {
+        public boolean remove(Object x, Object y) { return false; }
+    }
+
+    public abstract class MyMapStringInvalid implements Map<String, Integer> {
+        public boolean remove(String x, Integer y) { return false; }
+    }
+}