Drop a redundant CR cleanup

Commit 77779166569da389de44075b3d03413b353046a4 (Remove stray
CR from input, 2017-03-09) had introducing the removal of CR
from CRLF generated by MSVC's cl.exe -showIncludes.

Then, commit e9b9a456221b4b0660f90efa1ee092ea00c2c728 (gbuild:
strip away unexpected CR char at the end of Windows filenames,
2017-07-26) added a replacement doing the same, but using a
literal CR instead of "\r". It had in its commit message:

> seen with 2013 on libreoffice-5-2, but there is no
> indication that 2015 on master would be different

libreoffice-5-3-branch-point was tagged on 2016-11-23 (commit
4136757b4e51c4e6f7cb4132c95538a7f831ef2c), so the 5-2 branch
did not contain the former change, and so the premise that
"master would be no different" was likely incorrect.

Change-Id: If992eb826c5d6c2868c9bd706ae51847fe69eda7
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/159754
Tested-by: Jenkins
Reviewed-by: Mike Kaganski <mike.kaganski@collabora.com>

solenv/gbuild/platform/filter-showIncludes.awk

@@ -45,13 +45,6 @@ BEGIN {
     if (index($0, showincludes_prefix) == 1) {
         $0 = substr($0, length(showincludes_prefix) + 1)
         sub(/^ */, "")
-
-        # The output from MSVC may contain a carriage return character at the
-        # end of filenames, in which case the translation unit will depend on a
-        # non-existing header, resulting in constant rebuild of all files,
-        # prevent that.
-        sub(/
/, "")
-
         gsub(/\\/, "/")
         gsub(/ /, "\\ ")
         if ($0 ~ allowlist) { # filter out system headers