deps: V8: fix debug backtrace for symbols

The cherry-pick of nodejs#7612 to v4.x (4369055) added in nodejs#9298 wasn't quite
correct as it depends on a runtime function %SymbolDescriptiveString
that doesn't exist on v4.x. We can use %SymbolDescription instead.

Ref: nodejs#7612
Ref: nodejs#9298

Author: ofrobots

deps/v8/src/mirror-debugger.js

@@ -1515,7 +1515,7 @@ PropertyMirror.prototype.name = function() {
 
 
 PropertyMirror.prototype.toText = function() {
-  if (IS_SYMBOL(this.name_)) return %SymbolDescriptiveString(this.name_);
+  if (IS_SYMBOL(this.name_)) return %SymbolDescription(this.name_);
   return this.name_;
 };
 

deps/v8/test/mjsunit/debug-backtrace-text.js

@@ -106,7 +106,7 @@ function listener(event, exec_state, event_data, data) {
         // 2: [anonymous]
         assertEquals("new Point(x=0, y=0)",
                      exec_state.frame(0).invocationText());
-        assertEquals("#<Object>[Symbol(Das Symbol)](x=0, y=0)",
+        assertEquals("#<Object>[Das Symbol](x=0, y=0)",
                      exec_state.frame(1).invocationText());
         assertEquals("[anonymous]()", exec_state.frame(2).invocationText());
         listenerCalled = true;