Allow to extend and override the sanitizers options

Summary:
This cause the values from the user environment to be appended to the
options, allowing for adding options or overriding some. Update the CI
to use this feature.

Test Plan: Run the build-asan, build-ubsan and build-tsan CI builds.

Differential Revision: https://reviews.bitcoinabc.org/D5695

cmake/modules/Sanitizers.cmake

@@ -46,13 +46,13 @@ https://docs.bitcoincashnode.org/doc/fuzzing/")
 	include(TestSuite)
 	set(SAN_SUPP_DIR "${CMAKE_SOURCE_DIR}/test/sanitizer_suppressions")
 	if("address" IN_LIST ARGN)
-		add_test_environment(ASAN_OPTIONS malloc_context_size=0)
-		add_test_environment(LSAN_OPTIONS "suppressions=${SAN_SUPP_DIR}/lsan")
+		add_test_environment(ASAN_OPTIONS "malloc_context_size=0:$ENV{ASAN_OPTIONS}")
+		add_test_environment(LSAN_OPTIONS "suppressions=${SAN_SUPP_DIR}/lsan:$ENV{LSAN_OPTIONS}")
 	endif()
 	if("thread" IN_LIST ARGN)
-		add_test_environment(TSAN_OPTIONS "suppressions=${SAN_SUPP_DIR}/tsan")
+		add_test_environment(TSAN_OPTIONS "suppressions=${SAN_SUPP_DIR}/tsan:$ENV{TSAN_OPTIONS}")
 	endif()
 	if("undefined" IN_LIST ARGN)
-		add_test_environment(UBSAN_OPTIONS "suppressions=${SAN_SUPP_DIR}/ubsan:print_stacktrace=1:halt_on_error=1")
+		add_test_environment(UBSAN_OPTIONS "suppressions=${SAN_SUPP_DIR}/ubsan:print_stacktrace=1:halt_on_error=1:$ENV{UBSAN_OPTIONS}")
 	endif()
 endfunction()