The interrupts are already postponed in message handlers [1]. This CL aligns debug event listener (the mechanism that is actually used in Chrome DevTools) implementation with that. Handling interrupts on events like v8::AfterCompile leads to crashes like the one in the lined bug. This happens because in the interrupt handler we may change debugger state.

[1] https://codereview.chromium.org/309533009/diff/40001/src/debug.cc

BUG=chromium:520702
LOG=Y

Review URL: https://codereview.chromium.org/1321263002

Cr-Commit-Position: refs/heads/master@{#30488}