[C99] Update paper number tracked for arrays & lvalues; NFC

I finally found the original paper proposing the changes, so this
updates the test name, comments, and status page but is otherwise NFC.

Author: AaronBallman

clang/test/C/C99/array-lvalue.c renamed to clang/test/C/C99/n835.c

@@ -3,13 +3,10 @@
    expected-no-diagnostics
  */
 
-/* WG14 ???: Yes
+/* WG14 N835: Yes
  * Conversion of array to pointer not limited to lvalues
  *
- * NB: the original paper number is unknown, this was gleaned from the editor's report
- * in the C99 foreword. The C99 rationale document did not shed much light on
- * the situation either, mostly talking about user confusion between lvalue and
- * modifiable lvalue. However, the crux of the change was C89 changing:
+ * NB: The crux of the change was C99 changing:
  *
  * C89 3.2.2.1: Except when it is the operand of ..., an lvalue that has type
  * 'array of type' is converted to an expression that has type 'pointer to

clang/www/c_status.html

@@ -359,7 +359,7 @@ <h2 id="c99">C99 implementation status</h2>
     </tr>
     <tr>
       <td>conversion of array to pointer not limited to lvalues</td>
-      <td>Unknown</td>
+      <td>N835</td>
       <td class="full" align="center">Yes</td>
     </tr>
     <tr>