bpo-30673: test.bat: add -t option (timeout) (#2211)

Tools/buildbot/test.bat

 @echo off
-rem Used by the buildbot "test" step.
+rem Script to run the Python test suite used by the "test" step
+rem of Windows buildbot slaves.
+rem
+rem See PCbuild/rt.bat for options, extra options:
+rem  -t TIMEOUT: set a timeout in seconds
+
 setlocal
 
 set here=%~dp0
 set rt_opts=-q -d
 set regrtest_args=-j1
 
+rem Use a timeout of 20 minutes per test file by default
+set timeout=1200
+
 :CheckOpts
 if "%1"=="-x64" (set rt_opts=%rt_opts% %1) & shift & goto CheckOpts
 if "%1"=="-d" (set rt_opts=%rt_opts% %1) & shift & goto CheckOpts
@@ -13,7 +21,8 @@ if "%1"=="-O" (set rt_opts=%rt_opts% %1) & shift & goto CheckOpts
 if "%1"=="-q" (set rt_opts=%rt_opts% %1) & shift & goto CheckOpts
 if "%1"=="+d" (set rt_opts=%rt_opts:-d=%) & shift & goto CheckOpts
 if "%1"=="+q" (set rt_opts=%rt_opts:-q=%) & shift & goto CheckOpts
+if "%1"=="-t" (set timeout=%2) & shift & shift & goto CheckOpts
 if NOT "%1"=="" (set regrtest_args=%regrtest_args% %1) & shift & goto CheckOpts
 
 echo on
-call "%here%..\..\PCbuild\rt.bat" %rt_opts% -uall -rwW --slowest --timeout=1200 %regrtest_args%
+call "%here%..\..\PCbuild\rt.bat" %rt_opts% -uall -rwW --slowest --timeout=%timeout% %regrtest_args%