Remove separate test files in favor of same-file mod tests (#9199)

## Summary

These were moved as part of a broader refactor to create a single
integration test module. That "single integration test module" did
indeed have a big impact on compile times, which is great! But we aren't
seeing any benefit from moving these tests into their own files (despite
the claim in [this blog
post](https://matklad.github.io/2021/02/27/delete-cargo-integration-tests.html),
I see the same compilation pattern regardless of where the tests are
located). Plus, we don't have many of these, and same-file tests is such
a strong Rust convention.

crates/uv-python/src/libc.rs

@@ -235,4 +235,45 @@ fn find_ld_path_at(path: impl AsRef<Path>) -> Option<PathBuf> {
 }
 
 #[cfg(test)]
-mod tests;
+mod tests {
+    use super::*;
+    use indoc::indoc;
+
+    #[test]
+    fn parse_ldd_output() {
+        let ver_str = glibc_ldd_output_to_version(
+            "stdout",
+            indoc! {br"ld.so (Ubuntu GLIBC 2.39-0ubuntu8.3) stable release version 2.39.
+            Copyright (C) 2024 Free Software Foundation, Inc.
+            This is free software; see the source for copying conditions.
+            There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A
+            PARTICULAR PURPOSE.
+        "},
+        )
+        .unwrap();
+        assert_eq!(
+            ver_str,
+            LibcVersion::Manylinux {
+                major: 2,
+                minor: 39
+            }
+        );
+    }
+
+    #[test]
+    fn parse_musl_ld_output() {
+        // This output was generated by running `/lib/ld-musl-x86_64.so.1`
+        // in an Alpine Docker image. The Alpine version:
+        //
+        // # cat /etc/alpine-release
+        // 3.19.1
+        let output = b"\
+musl libc (x86_64)
+Version 1.2.4_git20230717
+Dynamic Program Loader
+Usage: /lib/ld-musl-x86_64.so.1 [options] [--] pathname [args]\
+    ";
+        let got = musl_ld_output_to_version("stderr", output).unwrap();
+        assert_eq!(got, LibcVersion::Musllinux { major: 1, minor: 2 });
+    }
+}