Reimplement testrunner_data.tcl::trd_get_bin_name() to assume a .exe extension on all platforms not matching "unix", to avoid having to do file-exists checks.

Author: sgbeal

test/testrunner_data.tcl

@@ -693,12 +693,10 @@ proc trd_test_script_properties {path} {
 #
 #    trd_get_bin_name executable-file-name
 #
-# If file $bin exists, return $bin. Else if ${bin}.exe
-# exists, return that. Else error out.
+# If the tcl platform is "unix", return $bin, else return
+# ${bin}.exe.
 proc trd_get_bin_name {bin} {
   global tcl_platform
-  if {[file exists $bin]} {return $bin}
-  if {[file exists $bin.exe]} {return $bin.exe}
-  if {$tcl_platform(platform)=="Windows"} {return $bin.exe}
-  return $bin
+  if {"unix" eq $tcl_platform(platform)} {return $bin}
+  return $bin.exe
 }