Add U+2212 to Japanese converters and update GBK/gb18030 aliases/tables

Add U+2212 to Japanese converters and update GBK/gb18030 aliases and tables.

1. Add a one-way (encoding-only/fromUnicode) mapping for U+2212 to
   Shift_JIS, EUC-JP and ISO-2022-JP. The last just uses Shift_JIS.

   See https://www.w3.org/Bugs/Public/show_bug.cgi?id=28661

2. Make GBK aliases list compliant to the encoding spec.

3. Add "xA3xA0 => U+3000" to the GBK (windows-936)  and gb18030. This makes it possible to remove the corresponding override in Blink

4. Modify the following to GBK (windows-936). See [1]
  - Add U+01F9 <=> \xA8\xBF
  - Drop U+E7C8 <=> \xA8\xBF

5. The following change is put on hold (NOT included in the CL)  until the resolution of [1]

  - Add U+1E3F <=> \xA8\xBC
  - Drop U+E7C7 <=> \xA8\xBC

The corresponding Blink CL is https://codereview.chromium.org/1167523003/

[1] https://www.w3.org/Bugs/Public/show_bug.cgi?id=28740#c3


BUG=425417, 493824
TEST=Once ICU is rolled to this CL, Blink layout test fast/encoding/*.
R=jsbell@chromium.org

Committed: https://chromium.googlesource.com/chromium/deps/icu/+/9939a5d5314b6d59d5fb070902d73304c2482f88

[jungshik at Google, 2015-06-02 00:14:21]

jshin@chromium.org changed reviewers:
+ jsbell@chromium.org

[jungshik at Google, 2015-06-02 00:14:21]

Not ready, yet. 

jsbell@: 
I wonder if you mind bundling two changes in a single CL: 1. U+2212 one-way
mapping (for Shift_JIS and EUC-JP) 2.  convrtrs.txt (GBK alias changes). 

The reason for bundling is that I'm a bit conscious of git repo size increase
due to ICU data files (2 * 10 + 2 * 25 + 6 = 56MB) having to be rebuilt for each
change.

[jsbell, 2015-06-02 00:16:44]

On 2015/06/02 00:14:21, jungshik at google wrote:
> I wonder if you mind bundling two changes in a single CL: 1. U+2212 one-way
> mapping (for Shift_JIS and EUC-JP) 2.  convrtrs.txt (GBK alias changes). 

SGTM. The U+2212 change is pretty non-controversial.

[jungshik at Google, 2015-06-04 13:13:27]

Now this CL is ready. Can you take a look? Thanks. 

#4 in the description is new. It will make our GBK a step closer to the encoding
spec and enable us to remove gbkFallback in Blink. (see
https://codereview.chromium.org/1167523003/ ). 

#5 is NOT done in the CL until the resolution of this issue in the spec.

[jungshik at Google, 2015-06-04 13:15:53]

On 2015/06/04 13:13:27, jungshik at google wrote:
> Now this CL is ready. Can you take a look? Thanks. 
> 
> #4 in the description is new. It will make our GBK a step closer to the
encoding
> spec and enable us to remove gbkFallback in Blink. (see
> https://codereview.chromium.org/1167523003/ ). 

Correction (forgot to mention that #3 is also new since PS#2)): #3 and #4 make
our GBK two code points closer to the spec (\xA3\xA0 and \xA8\xBF).

[jsbell, 2015-06-04 17:05:42]

lgtm

[jungshik at Google, 2015-06-04 19:24:50]

Committed patchset #6 (id:50001) manually as
9939a5d5314b6d59d5fb070902d73304c2482f88 (presubmit successful).