Re-enable most lldb-vscode tests on Linux.
I tried enabling all of them on my machine, and got two failures:
- One of them was spawning a child process that lives for 5 seconds, waited for 5 seconds to attach to the child, and failed because the child wasn't there.
- The other one was a legit failure because shell expansion of arguments doesn't work on Linux.
This tests enables all lldb-vscode tests on Linux except for "launch process
with shell expansion of args" (which doesn't work), and fixes the other broken
test by reducing the time it waits before attaching to its child process.
Reviewers: zturner, clayborg
Differential Revision: https://reviews.llvm.org/D60153