Skip `test_filepath` of "unparser/corpus/literal/def.txt"

The previous commit changes Ripper lex state behavior of `tLABEL`.
For example, Ripper lex state for the second `bar` was changed
by the previous commit.

```
def foo(bar: bar())
end
```

Before the commit, Ripper didn’t add label `bar` id to `vtable`
because `formal_argument` function for Ripper didn’t return id
but returned `VALUE lhs`.
Therefore Ripper didn’t `SET_LEX_STATE(EXPR_END|EXPR_LABEL)` for following `bar`
in `parse_ident` because `lvar_defined` for following `bar` was not true.

Currently Ripper does `SET_LEX_STATE(EXPR_END|EXPR_LABEL)` then
the result of this test case is changed like below.

```
Prism::ParseTest#test_filepath_unparser/corpus/literal/def.txt [ruby/test/prism/parse_test.rb:280]:
<[[80, 13], :on_ident, “bar”, END|LABEL]> expected but was
<[[80, 13], :on_ident, “bar”, ARG]>.
```

Parser sets lex state to `END|LABEL` on master branch.
Therefore previous commit makes Ripper’s behavior aligned with parser’s behavior.

```
$ ruby -v -y -e "def foo(bar: bar())" -e "end"
ruby 3.4.0dev (2024-02-11T23:52:05Z master 697ade7bda) [arm64-darwin21]
...
Reading a token
parser_dispatch_scan_event:11210 (1: 12|1|7)
lex_state: ARG|LABELED -> ARG at line 11113
lex_state: ARG -> END|LABEL at line 11128
parser_dispatch_scan_event:11877 (1: 13|3|4)
Next token is token “local variable or method” (1.13-1.16: bar)
Shifting token “local variable or method” (1.13-1.16: bar)
```

1 files changed, 2 insertions, 0 deletions

diff --git a/test/prism/parse_test.rb b/test/prism/parse_test.rb
index 574a1c1714..55b8c0178e 100644
--- a/test/prism/parse_test.rb
+++ b/test/prism/parse_test.rb
@@ -207,6 +207,8 @@ module Prism
       # https://bugs.ruby-lang.org/issues/19539
       ripper_should_parse = false if relative == "heredocs_leading_whitespace.txt" && RUBY_VERSION < "3.3.0"
 
+      ripper_should_parse = false if relative == "unparser/corpus/literal/def.txt"
+
       define_method "test_filepath_#{relative}" do
         # First, read the source from the filepath. Use binmode to avoid converting CRLF on Windows,
         # and explicitly set the external encoding to UTF-8 to override the binmode default.