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_env.rs

@@ -0,0 +1,29 @@
+use crate::repl::tests::{fail_test, run_test, TestResult};
+use nu_test_support::nu;
+
+#[test]
+fn shorthand_env_1() -> TestResult {
+    run_test(r#"FOO=BAZ $env.FOO"#, "BAZ")
+}
+
+#[test]
+fn shorthand_env_2() -> TestResult {
+    fail_test(r#"FOO=BAZ FOO=MOO $env.FOO"#, "defined_twice")
+}
+
+#[test]
+fn shorthand_env_3() -> TestResult {
+    run_test(r#"FOO=BAZ BAR=MOO $env.FOO"#, "BAZ")
+}
+
+#[test]
+fn default_nu_lib_dirs_type() {
+    let actual = nu!("$env.NU_LIB_DIRS | describe");
+    assert_eq!(actual.out, "list<string>");
+}
+
+#[test]
+fn default_nu_plugin_dirs_type() {
+    let actual = nu!("$env.NU_PLUGIN_DIRS | describe");
+    assert_eq!(actual.out, "list<string>");
+}