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_help.rs

@@ -0,0 +1,27 @@
+use crate::repl::tests::{run_test, TestResult};
+use rstest::rstest;
+
+#[rstest]
+// avoid feeding strings containing parens to regex.  Does not end well.
+#[case(": arga help")]
+#[case("argb help")]
+#[case("optional, default: 20")]
+#[case("- f1 switch")]
+#[case("- f2 named no default")]
+#[case("- f3 named default 3")]
+#[case("default: 33")]
+#[case("--help - Display the help message")]
+fn can_get_help(#[case] exp_result: &str) -> TestResult {
+    run_test(
+        &format!(
+            r#"def t [a:string, # arga help
+            b:int=20, # argb help
+            --f1, # f1 switch help
+            --f2:string, # f2 named no default
+            --f3:int=33 # f3 named default 3
+            ] {{ true }};
+            help t | ansi strip | find `{exp_result}` | get 0 | str replace --all --regex '^(.*({exp_result}).*)$' '$2'"#,
+        ),
+        exp_result,
+    )
+}