removes gitattributes for turbopack files (#8922)

with turbopack being removed in
#8906, we can also remove these
gitattributes files

.gitattributes

@@ -1,5 +1,3 @@
 .config/ast-grep/rule-tests/__snapshots__/** linguist-generated=true
 crates/turbo-tasks-macros-tests/tests/**/*.stderr linguist-generated=true
-crates/turbopack-ecmascript/tests/tree-shaker/analyzer/**/output.md linguist-generated=true
-crates/turbopack-tests/tests/snapshot/**/output/** linguist-generated=true
 crates/turborepo-lockfiles/fixtures/*.lock text eol=lf