Remove DEBUG_OUTPUT flag to prevent CI log overflow.

8 jobs for aptool_fortification in 16 minutes and 40 seconds
Name Stage Failure
failed
mac_llvm_testing Test
radix    =  57.79 sec*proc (39 tests)

Total Test time (real) = 57.90 sec
UpdateCTestConfiguration from :/Users/jap/builds/df563b7c/1/jap/radix/build/DartConfiguration.tcl
Parse Config file:/Users/jap/builds/df563b7c/1/jap/radix/build/DartConfiguration.tcl
Memory check project /Users/jap/builds/df563b7c/1/jap/radix/build
Memory checker (MemoryCheckCommand) not set, or cannot find the specified program.
Errors while running CTest
ERROR: Job failed: exit status 1
failed
mac_gcc_testing Test
radix    =  52.54 sec*proc (42 tests)

Total Test time (real) = 52.58 sec
UpdateCTestConfiguration from :/Users/jap/builds/df563b7c/0/jap/radix/build/DartConfiguration.tcl
Parse Config file:/Users/jap/builds/df563b7c/0/jap/radix/build/DartConfiguration.tcl
Memory check project /Users/jap/builds/df563b7c/0/jap/radix/build
Memory checker (MemoryCheckCommand) not set, or cannot find the specified program.
Errors while running CTest
ERROR: Job failed: exit status 1