This invariant will save us some head ache.
The changes to test-debug/DebugStub is due to the fact that it abuses
the ability to set break points in code that has no debug break slots.
This is now no longer possible.

R=ulan@chromium.org
BUG=v8:4132
LOG=N

Review URL: https://codereview.chromium.org/1181013007

Cr-Commit-Position: refs/heads/master@{#29038}

BUG=chromium:424142
LOG=N
R=jarin@chromium.org

Review URL: https://codereview.chromium.org/692453002

Cr-Commit-Position: refs/heads/master@{#24970}
git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@24970 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

This reverts commit r24964.

TBR=machenbach@chromium.org

Review URL: https://codereview.chromium.org/687163002

Cr-Commit-Position: refs/heads/master@{#24966}
git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@24966 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

R=ulan@chromium.org
BUG=chromium:424142
LOG=N

Review URL: https://codereview.chromium.org/685753002

Cr-Commit-Position: refs/heads/master@{#24964}
git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@24964 ce2b1a6d-e550-0410-aec6-3dcde31c8c00