Add more possessive quantifiers, unicode flag and support for more post-heredoc syntax, fix test file syntax being invalid

src/Composer/Autoload/ClassMapGenerator.php

@@ -248,19 +248,19 @@ class ClassMapGenerator
         // strip heredocs/nowdocs
         $contents = preg_replace('{
             # opening heredoc/nowdoc delimiter (word-chars)
-            <<<[ \t]*([\'"]?)(\w+)\\1
+            <<<[ \t]*+([\'"]?)(\w++)\\1
             # needs to be followed by a newline
             (?:\r\n|\n|\r)
             # the meat of it, matching line by line until end delimiter
             (?:
                 # a valid line is optional white-space (possessive match) not followed by the end delimiter, then anything goes for the rest of the line
-                [\t ]*+(?!\\2 [\t \r\n]*[;,.)])[^\r\n]*
+                [\t ]*+(?!\\2 \b)[^\r\n]*+
                 # end of line(s)
-                [\r\n]+
+                [\r\n]++
             )*
             # end delimiter
-            [\t ]* \\2 (?=[\t \r\n]*[;,.)])
-        }x', 'null', $contents);
+            [\t ]*+ \\2 (?=\b)
+        }xu', 'null', $contents);
 
         // strip strings
         $contents = preg_replace('{"[^"\\\\]*+(\\\\.[^"\\\\]*+)*+"|\'[^\'\\\\]*+(\\\\.[^\'\\\\]*+)*+\'}s', 'null', $contents);