RFR: 11u: Remove SymbolTable dependency from serviceability agent

[Lindenmaier, Goetz]

Hi,

I would like to downport this for parity with 11.0.9-oracle.
Please review:
cr.openjdk.java.net/~goetz/wr20/remove_symbol_table/

In HeapHprofBinWriter.java an additional if check hinders automatic patching.
Further down the code in the context differs.
I adapted the assertion that got added here.

Passed our testing.

Best regards,
  Goetz.