Squeeze the layout of expression nodes a bit.

Again 112MB less peak memory usage in the bug mentioned below. :-)
Routed all writes to to_boolean_types_ through its setter on the way.

BUG=417697
LOG=y
R=mvstanton@chromium.org

Review URL: https://codereview.chromium.org/615423006

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@24393 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Revert of Extend CPU profiler with mapping ticks to source lines (patchset #3 id:40001 of https://codereview.chromium.org/616963005/)

Reason for revert:
It broke layout test fast/events/window-onerror-02.html, error column reported by window.onerror is now wrong (I believe it is because of the change in full-codegen):

http://build.chromium.org/p/client.v8/builders/V8-Blink%20Linux%2064%20%28dbg%29/builds/652

Original issue's description:
> Extend CPU profiler with mapping ticks to source lines
>
> The idea behind of this solution is to use the existing "relocation info" instead of consumption the CodeLinePosition events emitted by the V8 compilers.
> During generation code and relocation info are generated simultaneously.
> When code generation is done you each code object has associated "relocation info".
> Relocation information lets V8 to mark interesting places in the generated code: the pointers that might need to be relocated (after garbage collection),
> correspondences between the machine program counter and source locations for stack walking.
>
> This patch:
> 1. Add more source positions info in reloc info to make it suitable for source level mapping.
> The amount of data should not be increased dramatically because (1) V8 already marks interesting places in the generated code and
> (2) V8 does not write redundant information (it writes a pair (pc_offset, pos) only if pos is changed and skips other).
> I measured it on Octane benchmark - for unoptimized code the number of source positions may achieve 2x ('lin_solve' from NavierStokes benchmark).
>
> 2. When a sample happens, CPU profiler finds a code object by pc, then use its reloc info to match the sample to a source line.
> If a source line is found that hit counter is increased by one for this line.
>
> 3. Add a new public V8 API to get the hit source lines by CDT CPU profiler.
> Note that it's expected a minor patch in Blink to pack the source level info in JSON to be shown.
>
> 4.Add a test that checks how the samples are distributed through source lines.
> It tests two cases: (1) relocation info created during code generation and (2) relocation info associated with precompiled function's version.
>
> Patch from Denis Pravdin <denis.pravdin@intel.com>
> BUG=None
> LOG=Y
> R=svenpanne@chromium.org
>
> Committed: https://code.google.com/p/v8/source/detail?r=24389

TBR=svenpanne@chromium.org,danno@chromium.org,alph@chromium.org,denis.pravdin@intel.com,weiliang.lin@intel.com
BUG=None
LOG=N

Review URL: https://codereview.chromium.org/624443005

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@24394 ce2b1a6d-e550-0410-aec6-3dcde31c8c00