Make CharSequence.length a function instead of property

And String.length as well.

This is done for JVM interoperability: java.lang.CharSequence is an open class
and has a function 'length()' which should be implemented in subclasses
somehow.

A minor unexpected effect of this is that String.length() is now a compile-time
constant (it wasn't such as a property because properties are not supported in
compile-time constant evaluation)

 #KT-3571 Fixed

compiler/testData/codegen/boxInline/complex/closureChain.1.kt

@@ -1,11 +1,10 @@
-
 fun test1(): Int {
     val inlineX = Inline()
-    return inlineX.foo({(z: Int) -> "" + z}, 25, {String.() -> this.length})
+    return inlineX.foo({(z: Int) -> "" + z}, 25, {String.() -> this.length()})
 }
 
 fun box(): String {
     if (test1() != 2) return "test1: ${test1()}"
 
     return "OK"
-}
+}

compiler/testData/codegen/boxInline/nonLocalReturns/tryFinally/callSite/exceptionTableSplit.2.kt

@@ -3,7 +3,7 @@ package test
 public class Holder(var value: String = "") {
 
     public fun plusAssign(s: String?) {
-        if (value.length != 0) {
+        if (value.length() != 0) {
             value += " -> "
         }
         value += s
@@ -30,4 +30,4 @@ public inline fun <R> doCallWithException(h: Holder, block: ()-> R) : R {
         h += "inline fun finally"
         throw RuntimeException("fail");
     }
-}
+}

compiler/testData/codegen/boxInline/nonLocalReturns/tryFinally/callSite/exceptionTableSplitNoReturn.2.kt

@@ -3,7 +3,7 @@ package test
 public class Holder(var value: String = "") {
 
     public fun plusAssign(s: String?) {
-        if (value.length != 0) {
+        if (value.length() != 0) {
             value += " -> "
         }
         value += s
@@ -30,4 +30,4 @@ public inline fun <R> doCallWithException(h: Holder, block: ()-> R) {
         h += "inline fun finally"
         throw RuntimeException("fail");
     }
-}
+}

compiler/testData/codegen/boxInline/nonLocalReturns/tryFinally/exceptionTable/tryCatchInFinally.2.kt

@@ -3,7 +3,7 @@ package test
 public class Holder(var value: String = "") {
 
     public fun plusAssign(s: String?) {
-        if (value.length != 0) {
+        if (value.length() != 0) {
             value += " -> "
         }
         value += s
@@ -33,4 +33,4 @@ public inline fun doCall(block: ()-> String, finallyBlock: ()-> String,
         }
     }
     return res
-}
+}