script files (.sc) do not strip multiline shebang

[bishabosha]

Version(s)
1.3.1

Describe the bug
If a script file (.sc) has a multiline shebang, then only the first line is stripped. Meaning the rest of the shebang is parsed as code by the Scala Compiler, leading to errors.

To Reproduce

make a file shebangTest.sc with the following content, and then run it with scala-cli run shebangTest.sc

#!/usr/bin/env fake-program-to-test-shebang-removal
# comment
STUFF=nada
!#
// everything above this point should be ignored by the compiler
def main(args: Array[String]): Unit =
  args.zipWithIndex.foreach { case (arg,i) => printf("arg %d: [%s]\n",i,arg) }
  System.err.printf("mainClassFromStack: %s\n",mainFromStack)
  assert(mainFromStack.contains("sheBang"),s"fromStack[$mainFromStack]")

  lazy val mainFromStack:String = {
    val result = new java.io.StringWriter()
    new RuntimeException("stack").printStackTrace(new java.io.PrintWriter(result))
    val stack = result.toString.split("[\r\n]+").toList
    if verbose then for( s <- stack ){ System.err.printf("[%s]\n",s) }
    stack.filter { str => str.contains(".main(") }.map {
      // derive main class name from stack when main object is NOT declared in source
      _.replaceAll("[.].*","").
      replaceAll("\\s+at\\s+","")
    }.distinct.take(1).mkString("")
  }

  lazy val verbose = Option(System.getenv("DOTC_VERBOSE")) match
    case None => false
    case _ => true

you should get errors like so:

-- Error: /Users/jamie/workspace/dotty/compiler/test-resources/scripting/.scala-build/scripting_6199f560ec-7ad3f4e164/src_generated/main/sheBang.scala:8:0
8 |# comment
  |^
  |end of statement expected but '#' found
-- [E006] Not Found Error: /Users/jamie/workspace/dotty/compiler/test-resources/scripting/.scala-build/scripting_6199f560ec-7ad3f4e164/src_generated/main/sheBang.scala:9:0
9 |STUFF=nada
  |^^^^^
  |Not found: STUFF
  |
  | longer explanation available when compiling with `-explain`
-- [E006] Not Found Error: /Users/jamie/workspace/dotty/compiler/test-resources/scripting/.scala-build/scripting_6199f560ec-7ad3f4e164/src_generated/main/sheBang.scala:9:6
9 |STUFF=nada
  |      ^^^^
  |      Not found: nada
  |
  | longer explanation available when compiling with `-explain`
-- [E006] Not Found Error: /Users/jamie/workspace/dotty/compiler/test-resources/scripting/.scala-build/scripting_6199f560ec-7ad3f4e164/src_generated/main/sheBang.scala:10:0
10 |!#
   |^^
   |Not found: !# - did you mean !=? or perhaps != or ## or ##?
   |
   | longer explanation available when compiling with `-explain`
4 errors found
Compilation failed

Expected behaviour
no errors, because the shebang should be stripped by scala-cli when wrapping the script source