Release: Increase timeout for slow-testing cygwin build

Previously, the ExternalProject test was timing out at the
default timeout value of 1500 seconds. Give it time, little
one, it will finish if you learn patience.

Utilities/Release/dash2win64_cygwin.cmake

@@ -8,6 +8,7 @@ set(CPACK_SOURCE_GENERATORS "CygwinSource")
 set(MAKE_PROGRAM "make")
 set(INITIAL_CACHE "CMAKE_BUILD_TYPE:STRING=Release
 CMAKE_Fortran_COMPILER_FULLPATH:FILEPATH=FALSE
+DART_TESTING_TIMEOUT:STRING=7200
 ")
 set(CXX g++)
 set(CC  gcc)