Fix currency tests for locales that don't return $ as USD symbol

Author: lhotari

grails-databinding/src/test/groovy/org/grails/databinding/converters/CurrencyConversionSpec.groovy

@@ -18,7 +18,7 @@ class CurrencyConversionSpec extends Specification {
 
         then:
         bank.currency instanceof Currency
-        '$' == bank.currency.symbol
+        'USD' == bank.currency.currencyCode
     }
 }
 

grails-test-suite-persistence/src/test/groovy/org/codehaus/groovy/grails/orm/GrailsWebDataBinderSpec.groovy

@@ -1296,7 +1296,7 @@ class GrailsWebDataBinderSpec extends Specification {
 
         then:
         publisher.localCurrency instanceof Currency
-        '$' == publisher.localCurrency.symbol
+        'USD' == publisher.localCurrency.currencyCode
     }
 }