RFR: 8256675: Zero: purge biased locking support

[Aleksey Shipilev]

Biased locking support was always disabled for C++ interpreter. Zero seems to have inherited that, see block in `arguments.cpp`:

#ifdef ZERO
  // Clear flags not supported on zero.
  FLAG_SET_DEFAULT(ProfileInterpreter, false);
  FLAG_SET_DEFAULT(UseBiasedLocking, false);
  LP64_ONLY(FLAG_SET_DEFAULT(UseCompressedOops, false));
  LP64_ONLY(FLAG_SET_DEFAULT(UseCompressedClassPointers, false));
#endif // ZERO

But `zero/bytecodeInterpreter.cpp` still has paths that imply biased locking support. Seeing that biased locking can go away, and the cost/benefit balance of supporting it in Zero, it makes more sense to purge the long-time-disabled biased locking support from Zero.

Additional testing:
 - [x] Ad-hoc benchmark runs with `-XX:(-|+)UseBiasedLocking` (Zero is so slow that BL does not matter)

-------------

Commit messages:
 - 8256675: Zero: purge biased locking support

Changes: https://git.openjdk.java.net/jdk/pull/1322/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=1322&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8256675
  Stats: 237 lines in 1 file changed: 1 ins; 201 del; 35 mod
  Patch: https://git.openjdk.java.net/jdk/pull/1322.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/1322/head:pull/1322

PR: https://git.openjdk.java.net/jdk/pull/1322