Referencing a method closures should work with GStrings

foo.&"$bar" doesn't work as expected

We should be able to define method closures with gstring identifiers.

groovy> class MCTest {
groovy> void testMethod1()

{ println "m1" }

groovy> void testMethod2()

{ println "m2" }

groovy> }
groovy> mctest = new MCTest()
groovy> m = mctest.class.methods.name.grep(~/^test.*$/).collect

{ mctest.&"$it" }

groovy> m.each

{ it() }

groovy> go
org.codehaus.groovy.control.MultipleCompilationErrorsException: startup failed, CommandLine.groovy:
6: Unexpected node type: DYNAMIC_MEMBER found when expecting type: an identifier at line: 6 column:
67. File: CommandLine.groovy @ line 6, column 67.
1 error