tests: Switch to NONE contexts in exhaustive and ctime tests

src/tests_exhaustive.c

@@ -396,7 +396,7 @@ int main(int argc, char** argv) {
 
     while (count--) {
         /* Build context */
-        ctx = secp256k1_context_create(SECP256K1_CONTEXT_SIGN | SECP256K1_CONTEXT_VERIFY);
+        ctx = secp256k1_context_create(SECP256K1_CONTEXT_NONE);
         secp256k1_testrand256(rand32);
         CHECK(secp256k1_context_randomize(ctx, rand32));
 

src/valgrind_ctime_test.c

@@ -39,9 +39,7 @@ int main(void) {
         fprintf(stderr, "Usage: libtool --mode=execute valgrind ./valgrind_ctime_test\n");
         return 1;
     }
-    ctx = secp256k1_context_create(SECP256K1_CONTEXT_SIGN
-                                   | SECP256K1_CONTEXT_VERIFY
-                                   | SECP256K1_CONTEXT_DECLASSIFY);
+    ctx = secp256k1_context_create(SECP256K1_CONTEXT_DECLASSIFY);
     /** In theory, testing with a single secret input should be sufficient:
      *  If control flow depended on secrets the tool would generate an error.
      */