[lldb] Flush delayed breakpoints before eagerly changing one (#195815)
See the discussion in https://github.com/llvm/llvm-project/pull/192971
When LLDB makes the decision to eagerly send a breakpoint packet, it
should first ensure the delayed breakpoints are flushed, as they may
interfere with the eager breakpoint that is about to be changed.
Implementation note: we could have included the eager breakpoint in the
batch that is about to be flushed. However, it's important to get
information about the error status of this eager breakpoint, and the
current APIs dont make it easy to distinguish which breakpoint caused an
error.