* Add back V3 TransactionBuilder c'tor (#4587)
(cherry picked from commit 5bb38e455c)
* Regen isolated jar to fix failing test(s) (#4583)
https://github.com/corda/corda/pull/4541 removed TransactionBuilder c'tor (which was introduced post-V3) which the frozen isolated jar was using
(cherry picked from commit f592025273)
* Fixed AttachmentLoadingTests (#4565)
There were two issues:
* The original "sealing violation: can't seal package net.corda.nodeapi" issue was due to the isolated CorDapp containing some code in the net.corda.nodeapi namespace. This has been moved to the isolated namespace.
* The test was not correctly creating the second transaction with the dummy command
(cherry picked from commit 3b8347e150)
* Regen isolated.jar to make sure it's based on the branch
* Fixed incorrect attachment loading integration test
`AttachmentLoadingTests.test that attachments retrieved over the network are not used for code` was a false-positive - it was incorrect on multiple levels. Fixing it required updating the finance:isolated CorDapp, at which point it was given the new MANIFEST metadata for V4, and moved out of the net.corda.finance namespace to avoid package sealing issues.
The new test exposed a bug in the LedgerTransaction verification logic. This was cleaned up as it was too easy to verify on the wrong instance.
