[windows] Add folder to path while testing.

Some DLL are not installed, since they are only used for testing, but
they need to be in the PATH to allow some test binaries to execute
properly.

Author: drodriguez

utils/build-windows.bat

@@ -65,7 +65,7 @@ call :build_swift %exitOnError%
 
 call :build_lldb %exitOnError%
 
-path %source_root%\icu-%icu_version%\bin64;%install_directory%\bin;%build_root%\swift\libdispatch-prefix\bin;%PATH%;%ProgramFiles%\Git\usr\bin
+path %source_root%\icu-%icu_version%\bin64;%install_directory%\bin;%build_root%\swift\bin;%build_root%\swift\libdispatch-prefix\bin;%PATH%;%ProgramFiles%\Git\usr\bin
 call :test_swift %exitOnError%
 
 goto :end