Re-apply https://github.com/llvm/llvm-project/pull/87550 with fixes.
Details:
Some tests in fuchsia failed because of the newly added assertion.
This was because `GetExceptionBreakpoint()` could be called before
`g_dap.debugger` was initted.
The fix here is to just lazily populate the list in
GetExceptionBreakpoint() rather than assuming it's already been initted.
(There is some nuisance here because we can't simply just populate it in
DAP::DAP(), which is a global ctor and is called before
`SBDebugger::Initialize()` is called. )
35fa2ded2a