Merged tests to produce a single binary (#12826)

This PR should close #7147 

# Description
Merged src/tests into /tests to produce a single binary.

![image](https://github.com/nushell/nushell/assets/94604837/84726469-d447-4619-b6d1-2d1415d0f42e)

# User-Facing Changes
No user facing changes

# Tests + Formatting
Moved tests. Tollkit check pr pass.

# After Submitting

---------

Co-authored-by: Ian Manske <ian.manske@pm.me>

tests/repl/test_stdlib.rs

@@ -0,0 +1,21 @@
+use crate::repl::tests::{fail_test, run_test_std, TestResult};
+
+#[test]
+fn library_loaded() -> TestResult {
+    run_test_std("scope modules | where name == 'std' | length", "1")
+}
+
+#[test]
+fn prelude_loaded() -> TestResult {
+    run_test_std("shells | length", "1")
+}
+
+#[test]
+fn not_loaded() -> TestResult {
+    fail_test("log info", "")
+}
+
+#[test]
+fn use_command() -> TestResult {
+    run_test_std("use std assert; assert true; print 'it works'", "it works")
+}