Generic/UpperCaseConstantName: handle unconventional spacing and comments before define

This commit fixes false positives in the sniff when handling
unconventional spacing and comments before `define`. When checking to
see if the `define` found is not a method call, the sniff would
incorrectly exclude only whitespaces. But comments can also be placed
between `define` and one of the tokens the sniff looks for
(T_OBJECT_OPERATOR, T_DOUBLE_COLON or T_NULLSAFE_OBJECT_OPERATOR).

Looking for the first non-empty token before `define` fixes this
problem.

Author: rodrigoprimo

src/Standards/Generic/Sniffs/NamingConventions/UpperCaseConstantNameSniff.php

@@ -88,7 +88,7 @@ public function process(File $phpcsFile, $stackPtr)
         }
 
         // Make sure this is not a method call.
-        $prev = $phpcsFile->findPrevious(T_WHITESPACE, ($stackPtr - 1), null, true);
+        $prev = $phpcsFile->findPrevious(Tokens::$emptyTokens, ($stackPtr - 1), null, true);
         if ($tokens[$prev]['code'] === T_OBJECT_OPERATOR
             || $tokens[$prev]['code'] === T_DOUBLE_COLON
             || $tokens[$prev]['code'] === T_NULLSAFE_OBJECT_OPERATOR

src/Standards/Generic/Tests/NamingConventions/UpperCaseConstantNameUnitTest.inc

@@ -51,3 +51,8 @@ define
     'CommentsInUnconventionalPlaces',
     'value'
 );
+
+$foo-> /* comment */ define('bar');
+$foo?->
+// phpcs:ignore Stnd.Cat.SniffName -- for reasons.
+define('bar');