Removes unnecessary cwd and pipeline from various tests (#9202)

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Cleans up various tests that unnecessarily use the `cwd` argument of
`nu!`, and the `pipeline` function for single line commands. Also
replaces some unnecessary raw strings with normal strings. Part of
#8670.

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crates/nu-command/tests/commands/alias.rs

@@ -71,9 +71,8 @@ fn cant_alias_keyword() {
 
 #[test]
 fn alias_wont_recurse() {
-    let actual = nu!(
-        cwd: ".", pipeline(
-        r#"
+    let actual = nu!(pipeline(
+        "
             module myspamsymbol {
                 export def myfoosymbol [prefix: string, msg: string] {
                     $prefix + $msg
@@ -82,7 +81,7 @@ fn alias_wont_recurse() {
             use myspamsymbol myfoosymbol;
             alias myfoosymbol = myfoosymbol 'hello';
             myfoosymbol ' world'
-        "#
+        "
     ));
 
     assert_eq!(actual.out, "hello world");