Ensure consistent error message in phpdbg parser

This would be either $end or "end of file" depending on bison
version. Explicitly specify "end of command" instead, which seems
more appropriate in context.

Author: nikic

sapi/phpdbg/phpdbg_parser.y

@@ -39,6 +39,7 @@ ZEND_EXTERN_MODULE_GLOBALS(phpdbg)
 %define api.value.type {phpdbg_param_t}
 %define parse.error verbose
 
+%token END 0 "end of command"
 %token T_EVAL       "eval"
 %token T_RUN        "run"
 %token T_SHELL      "shell"

sapi/phpdbg/tests/bug76813.phpt

@@ -4,7 +4,7 @@ Bug #76813 (Access_violation_near_NULL_on_source_operand)
 "#!==)===\377\377\276\242="
 #!==)===\377\377\276\242=
 --EXPECT--
-prompt> [Parse Error: syntax error, unexpected input, expecting $end]
-prompt> [Parse Error: syntax error, unexpected # (pound sign), expecting $end]
-prompt> [Parse Error: syntax error, unexpected # (pound sign), expecting $end]
+prompt> [Parse Error: syntax error, unexpected input, expecting end of command]
+prompt> [Parse Error: syntax error, unexpected # (pound sign), expecting end of command]
+prompt> [Parse Error: syntax error, unexpected # (pound sign), expecting end of command]
 prompt>