Dartc: constant lists and maps can be modified.

[DartBot]

This issue was originally filed by ms...@unipro.ru

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What steps will reproduce the problem?
Run the following tests:
main() {
  (const []).addLast(1);
}

or

main() {
  (const {})["k1"] = 1;
}

What is the expected output? What do you see instead?
Expected: runtime error
Actual: tests execute without errors

What version of the product are you using? On what operating system?
Dartc r3931. OS: Ubuntu 10.04

Please provide any additional information below.

[DartBot]

This comment was originally written by zundel@google.com

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Added Area-Compiler, Duplicate labels.
Marked as being merged into #176.