Move dart2dart tests to new dedicated directory

R=floitsch@google.com

Review URL: https://codereview.chromium.org//398493002

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@38367 260f80e4-7a28-3924-810f-c04153c831b5
Add an SExpressionStringifier test

Tests if the stringifier successfully generates a string containing the keywords of all nodes. Currently fails since string generation is not yet implemented for all nodes.

R=floitsch@google.com

Review URL: https://codereview.chromium.org//396943002

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@38368 260f80e4-7a28-3924-810f-c04153c831b5
Add missing node visitors to SExpressionStringifier

R=floitsch@google.com

Review URL: https://codereview.chromium.org//394173002

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@38369 260f80e4-7a28-3924-810f-c04153c831b5
Convert ir.InvokeStatic.target to Entity

Constructing a mock IR representation for testing purposes requires
passing a target to ir.InvokeStatic(). Changing InvokeStatic.target
from an Element to an Entity vastly simplifies this.

R=johnniwinther@google.com

Review URL: https://codereview.chromium.org//396213002

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@38370 260f80e4-7a28-3924-810f-c04153c831b5
Move SExpressionStringifier to its own file

Purely cut & paste plus updating of imports.

R=floitsch@google.com

Review URL: https://codereview.chromium.org//399113002

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@38371 260f80e4-7a28-3924-810f-c04153c831b5