CLDR-18465 Remove Before Diocletian are from Coptic calendar

Author: sffc

common/main/en.xml

@@ -2909,6 +2909,16 @@ annotations.
 					</intervalFormats>
 				</dateTimeFormats>
 			</calendar>
+			<calendar type="coptic">
+				<eras>
+					<eraNames>
+						<era type="1">Anno Martyrum</era>
+					</eraNames>
+					<eraAbbr>
+						<era type="1">AM</era>
+					</eraAbbr>
+				</eras>
+			</calendar>
 			<calendar type="hebrew">
 				<months>
 					<monthContext type="format">

common/main/root.xml

@@ -663,8 +663,7 @@ Warnings: All cp values have U+FE0F characters removed. See /annotationsDerived/
 						<alias source="locale" path="../eraAbbr"/>
 					</eraNames>
 					<eraAbbr>
-						<era type="0">ERA0</era>
-						<era type="1">ERA1</era>
+						<era type="1">AM</era>
 					</eraAbbr>
 					<eraNarrow>
 						<alias source="locale" path="../eraAbbr"/>

common/supplemental/supplementalData.xml

@@ -4583,7 +4583,6 @@ XXX Code for transations where no currency is involved
         <calendar type="coptic">
           <calendarSystem type="other"/>
           <eras>
-              <era type="0" end="284-08-28" code="coptic-inverse"/>
               <era type="1" start="284-08-29" code="coptic"/>
           </eras>
         </calendar>