Use signatures instead of fq-names in special built-ins

It's necessary to distinguish overloads,
e.g. MutableMap.remove now has two versions

compiler/testData/diagnostics/testsWithJava8/targetedBuiltIns/concurrentMapRemove.kt

@@ -0,0 +1,20 @@
+import java.util.concurrent.*
+
+val concurrent: ConcurrentMap<String, Int> = null!!
+val concurrentHash: ConcurrentHashMap<String, Int> = null!!
+
+fun foo() {
+    // TODO: Too permissive
+    concurrent.remove("", 1)
+    concurrent.remove("", "")
+    concurrentHash.remove("", 1)
+    concurrentHash.remove("", "")
+
+    // Flexible types
+    concurrent.remove(null, 1)
+    concurrent.remove(null, null)
+
+    // @PurelyImplements
+    concurrentHash.remove(null, 1)
+    concurrentHash.remove(null, null)
+}

compiler/testData/diagnostics/testsWithJava8/targetedBuiltIns/concurrentMapRemove.txt

@@ -0,0 +1,5 @@
+package
+
+public val concurrent: java.util.concurrent.ConcurrentMap<kotlin.String, kotlin.Int>
+public val concurrentHash: java.util.concurrent.ConcurrentHashMap<kotlin.String, kotlin.Int>
+public fun foo(): kotlin.Unit