[tools] winetest/gather: Use the report platform as the column header.

[Francois Gouget]

A group index page may contain reports from different but related
platforms, for instance Windows 8 and 8.1, or Windows 10 1507 and
1607. This allows immediately identifying a report's exact Windows
version.

Signed-off-by: Francois Gouget 
---
This seems more useful than repeating the group name which is already
present in the page title.
This patch uses the report id as is instead of trying to build a
pretty name like "Windows 8.1". It's simpler, seems readable enough, and
has the advantage of being short which is good as there are many
columns.
---
 winetest/gather | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/winetest/gather b/winetest/gather
index 09e4dfff1..ae754d977 100755
--- a/winetest/gather
+++ b/winetest/gather
@@ -294,9 +294,12 @@ foreach my $file (glob "$builddir/*/summary.txt") {
         next;
     }

-    my $report = { group => $group};
-    $report->{tag} = @tag?"@tag":"";
-    $report->{dir} = $dir;
+    my $report = {
+        id => $id,
+        group => $group,
+        tag => @tag ? "@tag" : "",
+        dir => $dir,
+    };
     if (!open TEST, "<$file") {
         error("could not open '$file' for reading: $!\n");
         next;
@@ -522,7 +525,7 @@ sub build_header_footer($)

if (!defined $msg) {
             $msg = <<"EOF";
-        $group->{name}<br><small>
+        $report->{id}<br><small>
         <a href="$report->{dir}/version.html">$report->{tag}</a></small>
 EOF
             chop $msg;