Bug 1487122 - fix icudata assembly for aarch64 windows; r=ted.mielczarek

Apparently the assembler was willing to accept the previous version, but
was unwilling to find the necessary symbols to link some JS code.  This
version correctly quotes the data symbol and adds a little extra quoting
based on examining compiler-generated output.

config/external/icu/data/genicudata.py

@@ -6,9 +6,9 @@
 
 
 def main(output, data_file, data_symbol):
-    output.write('''    AREA .rdata,ALIGN=4,DATA,READONLY
-    EXPORT _{data_symbol}[DATA]
-_{data_symbol}
+    output.write('''    AREA |.rdata|,ALIGN=4,DATA,READONLY
+    EXPORT |{data_symbol}|[DATA]
+|{data_symbol}|
     INCBIN {data_file}
     END
 '''.format(data_file=data_file, data_symbol=data_symbol))