This won't going to work for nested dummy_records, but you could try something like:

while (<DATA>) {
   print unless ((/<dummy_record>/../<\/dummy_record>/) || (/<dummy_re
+cord\/>/));
}

__DATA__
<?xml version="1.0">
<escinfo>
    <dbf>
        <progress>
            <record>
                <title>11111</title>
                <id>abcd</id>
            </record>
            <record>
                <title>22222</title>
                <id>efgh</id>
            </record>
        <dummy_record>
        <dummy>
                <title>22222</title>
                <id>efgh</id>
            </dummy>
        </dummy_record>
            <dummy_record/>
        </progress>
    </dbf>
</escinfo>
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