Getter, setter function name mangling issues

jjs> function f(){ void {get ""(){}} }f()

Expected: properly encoded byte code names
Actual: `f$get \=` method name in generated code (null prefix `\=` within name)

jjs> function f(){ void {get ":"(){}} }f()

Expected: properly encoded byte code names
Actual: `f$get \!` method name in generated code (missing null prefix `\=`)

jjs> function f(){ return Object.getOwnPropertyDescriptor({get ":"(){}}, ":").get.name }f()

Expected: don't return a mangled byte code name
Actual: returns "get \!"