Fix for issue 21579

Always generate the checkBigInt (Math.floor(x) == x) test for int receiver type checks and argument type checks, since the int32 tests don't make sense in the absence of bailouts.

Also remove dead code for checks that are no longer generated.

R=floitsch@google.com

Committed: https://code.google.com/p/dart/source/detail?r=42088

[sra1, 2014-12-03 01:20:52]

sra@google.com changed reviewers:
+ floitsch@google.com

[sra1, 2014-12-03 01:25:06]

Patchset #1 (id:1) has been deleted

[sra1, 2014-12-03 01:26:19]

https://codereview.chromium.org/763883004/diff/20001/pkg/compiler/lib/src/ssa...
File pkg/compiler/lib/src/ssa/codegen.dart (right):

https://codereview.chromium.org/763883004/diff/20001/pkg/compiler/lib/src/ssa...
pkg/compiler/lib/src/ssa/codegen.dart:2483: ||
checkedType.satisfies(backend.jsIndexableClass, classWorld));
If we remove this line, string checks on string-or-null change from

if (x == null) throw ...

to

if (typeof x != "string") throw ...

This is probably a benefit to V8 but maybe not other JS engines.
I see fiddling with this as a separate issue from un-breaking
--trust-type-annotations.

[floitsch, 2014-12-03 16:27:16]

LGTM.

[sra1, 2014-12-03 18:34:47]

Committed patchset #2 (id:40001) manually as 42088 (presubmit successful).