Need to update source exclusions for ICU 61

[srl295]

• Platform: all
• Subsystem: deps

#16876 landed ICU 60.1 but didn't update the source exclusions in icu_generic.gyp. As a result:

• too many files are built- increases binary size, and source size (this also controls what is checked into the repo)
• there's more exposure for platform build issues (probably a minor point)

This would cause NO change in actual behavior, because the files aren't actually executed (or their removal would have caused the build to fail).

[srl295]

should have read the guide in #7843 !

[srl295]

OK, looking at the exclusions: I only put them in for 55 and 57 (copy and paste). So they are missing for 56(#3281), 58 (#9234/#10206), 59 (#12486) AND 60 (#16876). So this is not a new issue.

Also fixing this now would break the floating patch #16931 without some care. (it could be re-applied)

Eminently back-port-able.

Instead of copy and paste, a range should be used for exclusions.

[srl295]

^ floating patch mentioned above is rolled into the #17687 so shouldn't be a problem.

[apapirovski]

@srl295 was this fixed when #17687 landed?

[srl295]

@apapirovski no, this a minor improvement is to add some more exclusions. It was unblocked by the above. Should now be 61 due to #19621

[jasnell]

@srl295 ... still needed?