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_conditionals.rs

@@ -0,0 +1,77 @@
+use crate::repl::tests::{run_test, TestResult};
+
+#[test]
+fn if_test1() -> TestResult {
+    run_test("if true { 10 } else { 20 } ", "10")
+}
+
+#[test]
+fn if_test2() -> TestResult {
+    run_test("if false { 10 } else { 20 } ", "20")
+}
+
+#[test]
+fn simple_if() -> TestResult {
+    run_test("if true { 10 } ", "10")
+}
+
+#[test]
+fn simple_if2() -> TestResult {
+    run_test("if false { 10 } ", "")
+}
+
+#[test]
+fn if_cond() -> TestResult {
+    run_test("if 2 < 3 { 3 } ", "3")
+}
+
+#[test]
+fn if_cond2() -> TestResult {
+    run_test("if 2 > 3 { 3 } ", "")
+}
+
+#[test]
+fn if_cond3() -> TestResult {
+    run_test("if 2 < 3 { 5 } else { 4 } ", "5")
+}
+
+#[test]
+fn if_cond4() -> TestResult {
+    run_test("if 2 > 3 { 5 } else { 4 } ", "4")
+}
+
+#[test]
+fn if_elseif1() -> TestResult {
+    run_test("if 2 > 3 { 5 } else if 6 < 7 { 4 } ", "4")
+}
+
+#[test]
+fn if_elseif2() -> TestResult {
+    run_test("if 2 < 3 { 5 } else if 6 < 7 { 4 } else { 8 } ", "5")
+}
+
+#[test]
+fn if_elseif3() -> TestResult {
+    run_test("if 2 > 3 { 5 } else if 6 > 7 { 4 } else { 8 } ", "8")
+}
+
+#[test]
+fn if_elseif4() -> TestResult {
+    run_test("if 2 > 3 { 5 } else if 6 < 7 { 4 } else { 8 } ", "4")
+}
+
+#[test]
+fn mutation_in_else() -> TestResult {
+    run_test(
+        "mut x = 100; if 2 > 3 { $x = 200 } else { $x = 300 }; $x ",
+        "300",
+    )
+}
+
+#[test]
+fn mutation_in_else2() -> TestResult {
+    run_test(
+        "mut x = 100; if 2 > 3 { $x = 200 } else if true { $x = 400 } else { $x = 300 }; $x ",
+        "400",
+    )
+}