qualified library names are not compiled

[DartBot]

This issue was originally filed by alexe.kaigorodov@gmail.com

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14 Libraries and Scripts reads:

libraryName:
  metadata library identifier (‘.’ identifier)* ‘;’
;

But VM gives compile error if library name is a qualified identifier:

'file:///home/kaigorodov/dash/dash/co19/tests/co19/src/Language/13_Libraries_and_Scripts/13_Libraries_and_Scripts_A03_t18.dart': Error: line 17 pos 18: semicolon expected
library Libraries.and.Scripts.A03.t18.lib;
                 ^

Affected test:
Language/13_Libraries_and_Scripts/13_Libraries_and_Scripts_A03_t18

[anders-sandholm]

Added Area-VM, Triaged labels.

[iposva-google]

Set owner to @mhausner.
Added this to the M3 milestone.
Added Accepted label.

[DartBot]

This comment was originally written by @mhausner

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Fixed with r15612.

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Added Fixed label.