Cleanup unused Dart API Dart_IdentityHash

Cleanup unused Dart API Dart_IdentityHash

There are a few problems with this function:
* It returns uint64_t instead of int64_t, which is different from
core Dart library function identityHashCode()
* Dart_IdentityHash truncates negative Mint and Bigint values to 0,
while negative Smi values are converted to uint64_t.

The Dart_IdentityHash function is not used, so we decided to remove it
instead of fixing these problems.

R=zra@google.com

Committed: https://github.com/dart-lang/sdk/commit/32e226be02ef1418a3c199b0336a4ea0e8f4d2fb

[alexmarkov, 2017-07-13 20:34:03]

alexmarkov@google.com changed reviewers:
+ asiva@google.com, rmacnak@google.com, zra@google.com

[zra, 2017-07-13 20:43:33]

lgtm

[alexmarkov, 2017-07-13 20:56:10]

Description was changed from

==========
Cleanup unused Dart API Dart_IdentityHash

There are a few problems with this function:
* It returns uint64_t instead of int64_t, which is different from
core Dart library function identityHashCode()
* Dart_IdentityHash truncates negative Mint and Bigint values to 0,
while negative Smi values are converted to uint64_t.

The Dart_IdentityHash function is not used, so we decided to remove it
instead of fixing these problems.
==========

to

==========
Cleanup unused Dart API Dart_IdentityHash

There are a few problems with this function:
* It returns uint64_t instead of int64_t, which is different from
core Dart library function identityHashCode()
* Dart_IdentityHash truncates negative Mint and Bigint values to 0,
while negative Smi values are converted to uint64_t.

The Dart_IdentityHash function is not used, so we decided to remove it
instead of fixing these problems.

R=zra@google.com

Committed:
https://github.com/dart-lang/sdk/commit/32e226be02ef1418a3c199b0336a4ea0e8f4d2fb
==========

[alexmarkov, 2017-07-13 20:56:11]

Committed patchset #1 (id:1) manually as
32e226be02ef1418a3c199b0336a4ea0e8f4d2fb (presubmit successful).