Remove python-like string multiplication (#10293)

# Description
Currently we support "multiplication" of strings, resulting in a terse
way to repeat a particular string.
This can have unintended side effects when dealing with mixed data (e.g.
after parsing data that is not all numbers).
Furthermore as we frequently fall-back to strings while parsing source
code, this introduced a runaway edge case in const evaluation (#10212)

Work for #10233

## Details
- Remove python-like string multiplication.
- Workaround for indentation
  - This should probably be addressed with a purpose built command
- Remove special const-eval error test

# User-Facing Changes
**Major breaking change!**
`"string" * 42` will stop working. (This was used for example in the
stdlib)

We should bless a good alternative before landing this

---------

Co-authored-by: JT <547158+jntrnr@users.noreply.github.com>

crates/nu-command/tests/commands/math/mod.rs

@@ -498,11 +498,3 @@ fn append_binary_values() {
     ));
     assert_eq!(actual.out, "0x[01020304]");
 }
-
-#[test]
-fn int_multiple_string() {
-    let actual = nu!(pipeline(r#"3 * "ab""#));
-    assert_eq!(actual.out, "ababab");
-    let actual = nu!(pipeline(r#""ab" * 3"#));
-    assert_eq!(actual.out, "ababab");
-}

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

@@ -214,14 +214,16 @@ mod regex {
 
     #[test]
     fn parse_handles_external_stream_chunking() {
-        Playground::setup("parse_test_streaming_1", |dirs, _sandbox| {
+        Playground::setup("parse_test_streaming_1", |dirs, sandbox| {
+            let data: String = std::iter::repeat("abcdefghijklmnopqrstuvwxyz")
+                .take(1000)
+                .collect();
+            sandbox.with_files(vec![Stub::FileWithContent("data.txt", &data)]);
+
             let actual = nu!(
-                cwd: dirs.test(), pipeline(
-                r#"
-                    "abcdefghijklmnopqrstuvwxyz" * 1000 | save --force data.txt;
-                    open data.txt | parse --regex "(abcdefghijklmnopqrstuvwxyz)" | length
-                "#
-            ));
+                cwd: dirs.test(),
+                r#"open data.txt | parse --regex "(abcdefghijklmnopqrstuvwxyz)" | length"#
+            );
 
             assert_eq!(actual.out, "1000");
         })