Steps towards unification of number bitset and range types.

Steps towards unification of number bitset and range types.

- New invariant on union types: if the union has a range then the number
  bits in the bitset must be cleared.

- Various tweaks in intersection and union to satisfy the invariant.

- Exposed and used representation bits in range types (and the Limits
  helper class).

- Implemented Glb for ranges so that the Is predicate handles
  ranges correctly.

- Change typer weakening so that it does not rely on GetRange.
  However, the code still seems to be a bit fragile.

- Removed the Smi types from the type system core, instead introduced
  Signed31, Unsigned30 and created constructors for Small(Un)Signed
  that point to the right type for the architecture.

- Punched a hole in the config to be able to get to the isolate so
  that it is possible to allocate heap numbers for newly created
  ranges.

Patch by jarin@chromium.prg, original review here:
https://codereview.chromium.org/795713003/

TBR=jarin@chromium.org
BUG=

Committed: https://crrev.com/2764fd8d1a266a9136c987c2483492113b0c8d80
Cr-Commit-Position: refs/heads/master@{#26197}

[rossberg, 2015-01-20 15:58:01]

The CQ bit was checked by rossberg@chromium.org

[commit-bot: I haz the power, 2015-01-20 15:58:24]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/837723006/20001

[rossberg, 2015-01-20 16:21:07]

The CQ bit was unchecked by rossberg@chromium.org

[rossberg, 2015-01-21 11:46:01]

The CQ bit was checked by rossberg@chromium.org

[commit-bot: I haz the power, 2015-01-21 11:46:15]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/837723006/40001

[commit-bot: I haz the power, 2015-01-21 11:52:37]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-01-21 11:52:40]

Try jobs failed on following builders:
  v8_linux_arm64_rel on tryserver.v8
(http://build.chromium.org/p/tryserver.v8/builders/v8_linux_arm64_rel/builds/2238)

[rossberg, 2015-01-21 12:01:43]

The CQ bit was checked by rossberg@chromium.org

[commit-bot: I haz the power, 2015-01-21 12:02:25]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/837723006/60001

[commit-bot: I haz the power, 2015-01-21 13:00:56]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-01-21 13:00:57]

Try jobs failed on following builders:
  v8_linux_arm_rel on tryserver.v8
(http://build.chromium.org/p/tryserver.v8/builders/v8_linux_arm_rel/builds/840)

[Jakob Kummerow, 2015-01-21 14:58:30]

The CQ bit was checked by jkummerow@chromium.org

[commit-bot: I haz the power, 2015-01-21 14:59:27]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/837723006/60001

[commit-bot: I haz the power, 2015-01-21 15:29:16]

Committed patchset #4 (id:60001)

[commit-bot: I haz the power, 2015-01-21 15:29:30]

Patchset 4 (id:??) landed as
https://crrev.com/2764fd8d1a266a9136c987c2483492113b0c8d80
Cr-Commit-Position: refs/heads/master@{#26197}

[Benedikt Meurer, 2015-01-22 05:32:50]

A revert of this CL (patchset #4 id:60001) has been created in
https://codereview.chromium.org/868583002/ by bmeurer@chromium.org.

The reason for reverting is: Breaks test-types/Maybe, i.e.

out/Release/cctest --random-seed=-707413401 test-types/Maybe

started failing afterwards.