The example in JDK-8334691 shows that most accessed ExternalAddress from code are strings:
 3005: 0x00007fa6e23c2e76 : 'should not reach here'
 5364: 0x00007fa6e24251b0 : 'uncommon trap return'

Add separate static table for such strings. Populate it during startup and use enum indexes from table in relocation info when they are used in code.
This will avoid locks when relocation references these strings.

Add tag to external_word_Relocation to indicate that it references stings.