deps: ICU 59 bump

[srl295]

It’s that time again.

• Platform: all
• Subsystem: deps

RC due 2017-03-31, GA 2017-04-14
backlink: ICU 58: #7844
depends on: #11753 and the v8 fixes mentioned therein

Semver-minor.

[ilovezfs]

Any updates here?

[srl295]

@ilovezfs thanks, was just going to see if there was anything new re: v8

[srl295]

@ilovezfs Cool. Last week the v8 fix landed . Now I don't need a floating patch, @MylesBorins