Fixes to make dbug traces from Windows easier to compare with Unix traces

- Remove DBUG calls from my_winfile.c where call and parameters
  are already printed by mysys.
- Remove DBUG from my_get_osfhandle() and my_get_open_flags() to remove
  DBUG noise.
- Updated convert-debug-for-diff to take into account windows.
- Changed some DBUG_RETURN(function()) to tmp=function(); DBUG_RETURN(tmp);
  This is needed as Visual C++ prints for DBUG binaries a trace for
  func_a()
  {
    DBUG_ENTER("func_a");
    DBUG_RETURN(func_b())
  }
  as
  >func_a
  <func_a
  >func_b
  <func_b
instead of when using gcc:
  >func_a
  | >func_b
  | <func_b
  <func_a

scripts/convert-debug-for-diff.sh

@@ -20,14 +20,16 @@ while (<>)
 {
   s/^T@[0-9]+ *://g;
   s/0x[0-9a-f]+(\s|\n|\)|=|,|;)/#$1/g;
+  s/bitmap: [0-9a-fA-F]+$/bitmap: #/g;
   s/size: [0-9-]+/size: #/g;
   s/memory_used: [0-9]+/memory_used: #/g;
+  s/memory_used: -[0-9]+/memory_used: #/g;
   s/Total alloc: [0-9]+/Total alloc: #/g;
   s/(proc_info: )(.*:)[\d]+ /$1 /;
   s/(select_cond.*) at line.*/$1/;
   s/\(id: \d+ -> \d+\)/id: #->#/g;
   s/(exit: found key at )\d+/$1#/g;
-  s/enter_stage: ([^\/]*)(\/.*\/)(.*)(:\d+)/enter_stage: ($1)/g;
+  s/enter_stage: (.* at).*/enter_stage $1 ../g;
   s/crc: [0-9]+/crc: #/g;
   s/ref_count: [0-9]+/ref_count: #/g;
   s/block: # \(\d+\)/block: # (#)/g;
@@ -37,6 +39,7 @@ while (<>)
   s/#sql_.*_(\d+)/#sql_xxx_$1/g;
   s/fd: [0-9]+/fd: #/g;
   s/query_id: (\d+)/query_id: #/g;
-  s|: .*/mysql-test/var/tmp/mysqld\.\d|d: var/tmp/mysqld|g;
+  s|: .*/mysql-test/var/tmp/mysqld\.\d|: var/tmp/mysqld|g;
+  s|: .*\\mysql-test\\var\\tmp\\mysqld\.\d|: var/tmp/mysqld|g;
   print $_;
 }