Split getClosureRepresentationInfo into MemberEntity and (ir/ast) nodes

tests/compiler/dart2js_extra/dart2js_extra.status

Index: tests/compiler/dart2js_extra/dart2js_extra.status
diff --git a/tests/compiler/dart2js_extra/dart2js_extra.status b/tests/compiler/dart2js_extra/dart2js_extra.status
index 0fed8a5983db90b3edeaa9c455fd1c7468409204..6e7bbcb852e239897f6c285a5e09e8e455fc706d 100644
--- a/tests/compiler/dart2js_extra/dart2js_extra.status
+++ b/tests/compiler/dart2js_extra/dart2js_extra.status
@@ -195,7 +195,6 @@ closure_capture3_test: Crash
 closure_capture4_test: Crash
 closure_capture4_test: RuntimeError
 closure_capture5_test: Crash
-closure_capture6_test: Crash
 closure_capture_test: Crash
 closure_capture_test: RuntimeError
 closure_type_reflection2_test: Crash
@@ -290,7 +289,8 @@ private_symbol_literal_test/05: MissingCompileTimeError
 private_symbol_literal_test/06: MissingCompileTimeError
 recursive_import_test: CompileTimeError
 reflect_native_types_test: Crash
-regress/4515_2_test: Crash
+closure4_test: RuntimeError
+closure_capture5_test: RuntimeError
 regress/4562_test/none: CompileTimeError
 regress/4639_test: Crash
 string_interpolation_dynamic_test: RuntimeError
@@ -332,7 +332,6 @@ closure_capture2_test: RuntimeError
 closure_capture3_test: Crash # Assertion failure: Cannot find value local(Closure_nestedClosure_closure.call#f) in (local(Closure.nestedClosure#)) for j:closure_call(Closure_nestedClosure_closure.call).
 closure_capture4_test: RuntimeError
 closure_capture5_test: Crash # Assertion failure: Cannot find value local(closure3_closure.call#fs) in (local(closure3#)) for j:closure_call(closure3_closure.call).
-closure_capture6_test: Crash # Assertion failure: Cannot find value local(captureTwiceNested_closure.call#x) in (local(captureTwiceNested#)) for j:closure_call(captureTwiceNested_closure.call).
 closure_capture_test: RuntimeError
 closure_type_reflection2_test: Crash # UnimplementedError: KernelClosedWorldMixin.getAppliedMixin
 closure_type_reflection_test: Crash # UnimplementedError: KernelClosedWorldMixin.getAppliedMixin
@@ -424,7 +423,8 @@ private_symbol_literal_test/05: MissingCompileTimeError
 private_symbol_literal_test/06: MissingCompileTimeError
 recursive_import_test: CompileTimeError
 reflect_native_types_test: Crash # UnimplementedError: KernelClosedWorldMixin.getAppliedMixin
-regress/4515_2_test: Crash # NoSuchMethodError: The getter 'name' was called on null.
+closure4_test: RuntimeError
+closure_capture5_test: RuntimeError
 regress/4562_test/none: CompileTimeError
 regress/4639_test: Crash # NoSuchMethodError: The getter 'enclosingClass' was called on null.
 runtime_type_test: Crash