[Travis] Enable cache with sapling tests

.github/workflows/build-and-test.yml

@@ -299,7 +299,7 @@ jobs:
             unit_tests: false
             functional_tests: true
             goal: install
-            test_runner_extra: "--tiertwo --sapling --skipcache"
+            test_runner_extra: "--tiertwo --sapling"
             BITCOIN_CONFIG: "--enable-zmq --with-gui=no --enable-glibc-back-compat --enable-reduce-exports --disable-online-rust"
 
           - name: x86_64 Linux  [GOAL:install]  [xenial]  [no depends only system libs]

.travis.yml

@@ -180,7 +180,7 @@ jobs:
         DEP_OPTS="NO_QT=1 NO_UPNP=1 DEBUG=1 ALLOW_HOST_PACKAGES=1"
         RUN_UNIT_TESTS=false
         RUN_FUNCTIONAL_TESTS=true
-        TEST_RUNNER_EXTRA="--tiertwo --sapling --skipcache"   # Run tier two and sapling functional tests only.
+        TEST_RUNNER_EXTRA="--tiertwo --sapling"   # Run tier two and sapling functional tests only.
         GOAL="install"
         BITCOIN_CONFIG="--with-gui=no --enable-glibc-back-compat --enable-reduce-exports --disable-online-rust --with-params-dir=$PARAMS_DIR"
         BUILD_TIMEOUT=800

test/functional/test_runner.py

@@ -145,11 +145,11 @@
 
 SAPLING_SCRIPTS = [
     # Longest test should go first, to favor running tests in parallel
-    'sapling_key_import_export.py',             # ~ 356 sec
+    'sapling_key_import_export.py',             # ~ 378 sec
     'sapling_wallet_anchorfork.py',             # ~ 345 sec
-    'sapling_wallet_nullifiers.py',             # ~ 201 sec
-    'sapling_wallet_listreceived.py',           # ~ 169 sec
-    'sapling_wallet.py',                        # ~ 164 sec
+    'sapling_wallet.py',                        # ~ 274 sec
+    'sapling_wallet_nullifiers.py',             # ~ 190 sec
+    'sapling_wallet_listreceived.py',           # ~ 157 sec
     'sapling_changeaddresses.py',               # ~ 151 sec
     'sapling_mempool.py',                       # ~ 98 sec
     'sapling_wallet_persistence.py',            # ~ 90 sec