cmake: Do not disable libsecp's constant time tests

This change mirrors the behavior of the master branch.

Author: hebasto

src/CMakeLists.txt

@@ -50,7 +50,6 @@ set(SECP256K1_ECMULT_GEN_KB 86 CACHE STRING "" FORCE)
 set(SECP256K1_BUILD_BENCHMARK OFF CACHE BOOL "" FORCE)
 set(SECP256K1_BUILD_TESTS ${BUILD_TESTS} CACHE BOOL "" FORCE)
 set(SECP256K1_BUILD_EXHAUSTIVE_TESTS ${BUILD_TESTS} CACHE BOOL "" FORCE)
-set(SECP256K1_BUILD_CTIME_TESTS OFF CACHE BOOL "" FORCE)
 set(SECP256K1_BUILD_EXAMPLES OFF CACHE BOOL "" FORCE)
 include(GetTargetInterface)
 # -fsanitize and related flags apply to both C++ and C,