Added missing .opp.exp files for 3 tests.

bench/good/grune924.opp.exp

+%start s
+%token LPAR
+%token MINUS
+%token N
+%token RPAR
+%type <unit> s
+%%
+
+s:
+  _1 = e
+    {    ( () )}
+
+e:
+  _1 = e _2 = MINUS _3 = t
+    {    ( () )}
+| _1 = t
+    {    ( () )}
+
+t:
+  _1 = N
+    {    ( () )}
+| _1 = LPAR _2 = e _3 = RPAR
+    {    ( () )}
+
+%%
+
+
+

bench/good/option2.opp.exp

+%start main
+%token FOO
+%type <unit> main
+%%
+
+main:
+  o = option2_option
+    {             ( o )}
+
+option2_option:
+  _1 = FOO
+    {      ( () )}
+
+%%
+
+
+
+Note: the nonterminal symbol option (from option2.mly) is renamed option2_option.

bench/good/pxp-ucs2_to_utf8.opp.exp

+%start main
+%token <int> CHAR
+%token END_OF_LET
+%token EOF
+%token EQ
+%token <string> IDENT
+%token LBRACKET
+%token LET
+%token PIPE
+%token RANGE
+%token RBRACKET
+%type <Types.definition list> main
+%%
+
+main:
+  _1 = EOF
+    {                    ( [] )}
+| _1 = declaration _2 = main
+    {                    ( _1::_2 )}
+
+declaration:
+  _1 = LET _2 = IDENT _3 = EQ _4 = regexp _5 = END_OF_LET
+    {      ( { Types.id = _2 ; Types.rel = _4 } )}
+
+regexp:
+  _1 = regexptoken _2 = PIPE _3 = regexp
+    {                            ( _1::_3 )}
+| _1 = regexptoken
+    {                            ( [_1] )}
+
+regexptoken:
+  _1 = CHAR
+    {                                      ( Types.Char _1 )}
+| _1 = LBRACKET _2 = CHAR _3 = RANGE _4 = CHAR _5 = RBRACKET
+    {                                      ( Types.Interval (_2,_4) )}
+| _1 = IDENT
+    {                                      ( Types.Identifier _1 )}
+
+%%
+
+
+