test: enable unit tests to work with variable reference fee (#5145)

Fix remaining unit tests to be able to process reference fee values other than 10.

src/test/app/MultiSign_test.cpp

@@ -141,6 +141,7 @@ public:
         Env env{*this, features};
         Account const alice{"alice", KeyType::ed25519};
         env.fund(XRP(1000), alice);
+        env.close();
 
         // Add alice as a multisigner for herself.  Should fail.
         env(signers(alice, 1, {{alice, 1}}), ter(temBAD_SIGNER));
@@ -888,6 +889,7 @@ public:
         Env env{*this, features};
         Account const alice{"alice", KeyType::ed25519};
         env.fund(XRP(1000), alice);
+        env.close();
 
         // There are three negative tests we need to make:
         //  M0. A lone master key cannot be disabled.
@@ -969,6 +971,7 @@ public:
         Env env{*this, features};
         Account const alice{"alice", KeyType::secp256k1};
         env.fund(XRP(1000), alice);
+        env.close();
 
         // Give alice a regular key with a zero fee.  Should succeed.  Once.
         Account const alie{"alie", KeyType::ed25519};
@@ -985,6 +988,7 @@ public:
         // fee should always fail.  Even the first time.
         Account const becky{"becky", KeyType::ed25519};
         env.fund(XRP(1000), becky);
+        env.close();
 
         env(signers(becky, 1, {{alice, 1}}), sig(becky));
         env(regkey(becky, alie), msig(alice), fee(0), ter(telINSUF_FEE_P));
@@ -1103,6 +1107,7 @@ public:
 
         Account const alice{"alice"};
         env.fund(XRP(1000), alice);
+        env.close();
         env(signers(alice, 1, {{bogie, 1}, {demon, 1}}), sig(alice));
 
         auto const baseFee = env.current()->fees().base;