revert adding a test, should have been part of 00cd7b8ca backport

tests/semreject/tmixing_return_and_exprs.nim

@@ -1,44 +0,0 @@
-discard """
-  errormsg: "expression 'len(src) shl 1' is of type 'int' and has to be discarded"
-  line: 19
-"""
-
-# bug #15280
-
-type
-  HexFlags* {.pure.} = enum
-    LowerCase,  ## Produce lowercase hexadecimal characters
-    PadOdd,     ## Pads odd strings
-    SkipSpaces, ## Skips all the whitespace characters inside of string
-    SkipPrefix  ## Skips `0x` and `x` prefixes at the begining of string
-
-
-proc bytesToHex*(src: openarray[byte], dst: var openarray[char],
-                 flags: set[HexFlags]): int =
-  if len(dst) == 0:
-    (len(src) shl 1)
-  else:
-    var halflast = false
-    let dstlen = len(dst)
-    var srclen = len(src)
-
-    if dstlen < (srclen shl 1):
-      if (dstlen and 1) == 1:
-        srclen = (dstlen - 1) shr 1
-        halflast = true
-      else:
-        srclen = (dstlen shr 1)
-
-    let lowercase = (HexFlags.LowerCase in flags)
-
-    var k = 0
-    for i in 0 ..< srclen:
-      let x = int(src[i])
-      inc(k, 2)
-
-    if halflast:
-      let x = int(src[srclen])
-      inc(k)
-
-    return k
-