Make a few tweaks to the changes in 43fe49e7

- This was the first merge after I got back from sabbatical. I made
  these same changes in "ximinez/lending-XLS-66" commit 9d052dc, but
  after seeing some test failures, I think they belong here.

src/test/jtx/impl/Env.cpp

@@ -218,7 +218,9 @@ Env::balance(Account const& account, MPTIssue const& mptIssue) const
         if (!sle)
             return {STAmount(mptIssue, 0), account.name()};
 
-        STAmount const amount{mptIssue, sle->getFieldU64(sfOutstandingAmount)};
+        // Make it negative
+        STAmount const amount{
+            mptIssue, sle->getFieldU64(sfOutstandingAmount), 0, true};
         return {amount, lookup(issuer).name()};
     }
     else

src/xrpld/app/tx/detail/Escrow.cpp

@@ -81,8 +81,8 @@ constexpr HashRouterFlags SF_CF_VALID = HashRouterFlags::PRIVATE6;
 TxConsequences
 EscrowCreate::makeTxConsequences(PreflightContext const& ctx)
 {
-    return TxConsequences{
-        ctx.tx, isXRP(ctx.tx[sfAmount]) ? ctx.tx[sfAmount].xrp() : beast::zero};
+    auto const amount = ctx.tx[sfAmount];
+    return TxConsequences{ctx.tx, isXRP(amount) ? amount.xrp() : beast::zero};
 }
 
 template <ValidIssueType T>