Revert "Rollup merge of rust-lang#71372 - ayushmishra2005:shebang_stripping, r=estebank"

This reverts commit 46a8dce, reversing
changes made to f28e387.

Author: eddyb

src/librustc_lexer/src/lib.rs

@@ -236,17 +236,12 @@ pub enum Base {
 /// (e.g. "#![deny(missing_docs)]").
 pub fn strip_shebang(input: &str) -> Option<usize> {
     debug_assert!(!input.is_empty());
-    let s: &str = &remove_whitespace(input);
-    if !s.starts_with("#!") || s.starts_with("#![") {
+    if !input.starts_with("#!") || input.starts_with("#![") {
         return None;
     }
     Some(input.find('\n').unwrap_or(input.len()))
 }
 
-fn remove_whitespace(s: &str) -> String {
-    s.chars().filter(|c| !c.is_whitespace()).collect()
-}
-
 /// Parses the first token from the provided input string.
 pub fn first_token(input: &str) -> Token {
     debug_assert!(!input.is_empty());

src/librustc_lexer/src/tests.rs

@@ -145,22 +145,4 @@ mod tests {
             }),
         );
     }
-
-    #[test]
-    fn test_valid_shebang() {
-        // https://github.com/rust-lang/rust/issues/70528
-        let input = "#!/usr/bin/rustrun";
-        let actual = strip_shebang(input);
-        let expected: Option<usize> = Some(18);
-        assert_eq!(expected, actual);
-    }
-
-    #[test]
-    fn test_invalid_shebang_valid_rust_syntax() {
-        // https://github.com/rust-lang/rust/issues/70528
-        let input = "#!    [bad_attribute]";
-        let actual = strip_shebang(input);
-        let expected: Option<usize> = None;
-        assert_eq!(expected, actual);
-    }
 }