Simplify tests (use shorter refinement syntax)

After ceylon/ceylon-compiler#1725 was fixed (thanks @tombentley), we can
finally use the following syntax:

    compile = compileBaseExpression;
    fromCeylon = RedHatTransformer.transformBaseExpression;
    toCeylon = baseExpressionToCeylon;

instead of the much more heavy-handed:

    shared actual BaseExpression? compile(String code) => compileBaseExpression(code);
    shared actual JBaseMemberOrTypeExpression fromCeylon(RedHatTransformer transformer)(BaseExpression node) => transformer.transformBaseExpression(node);
    shared actual BaseExpression toCeylon(JBaseMemberOrTypeExpression node) => baseExpressionToCeylon(node);

This was done with the following command:

    find source/test/ceylon/ast/redhat/ -name '[A-Z]*.ceylon' \
        -and -not -name 'TokenFactoryImpl.ceylon' \
        -and -not -name 'SimpleTokenFactory.ceylon' \
        -exec \
            sed -i \
            -e 's|shared .* compile(S.* \([[:alpha:]]*\)(code);|compile = \1;|' \
            -e 's|shared .* fromCeylon(R.* transformer\.\([[:alpha:]]*\)(node);|fromCeylon = RedHatTransformer.\1;|' \
            -e 's|shared .* [[:alpha:]]* toCeylon([[:alpha:]]* node) => \([[:alpha:]]*\)(node);|toCeylon = \1;|' \
        {} +