test/integ: parameterize, parallelize integ tests

## Problem:

integ tests are slow. and some of them (Java debug) are hard to cleanup, or interfere with each other.

## Solution

- add a parameter to the test runner that selects specific integ tests (including permutations of the test in `src/integrationTest/sam.test.ts`
- in our CI [buildspec](https://github.com/aws/aws-toolkit-vscode/blob/master/buildspec/linuxIntegrationTests.yml), define separate jobs for the various permutations (especially the "Java" case)
- revert the workaround from https://github.com/aws/aws-toolkit-vscode/pull/1999

Start with src/integrationTest/sam.test.ts to understand the test permutations and how the runner currently selects tests. Then inspect buildspec/linuxIntegrationTests.yml and PR 1999's workaround. Done means selected permutations can run in separate CI jobs, especially Java debug tests, without cleanup interference, and the workaround is reverted.

Written by the indexing model from the issue text.