RFR: 8253765: C2: Control randomization in StressLCM and StressGCM [v2]

[Roberto Castañeda Lozano]

> Use the compilation-local seed in `StressLCM` and `StressGCM` rather than the global one. As a consequence, these
> options use by default a fresh seed in every compilation, unless `StressSeed=N` is specified, in which case they behave
> deterministically. Annotate tests that use `StressLCM` and `StressGCM` with the `stress` and `randomness` keys to
> reflect this change in default behavior.  Tested on `tier1` and on all test cases that use `StressLCM` and `StressGCM`
> (10 times each).

Roberto Castañeda Lozano has updated the pull request incrementally with one additional commit since the last revision:

  Close parenthesis in option description

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/572/files
  - new: https://git.openjdk.java.net/jdk/pull/572/files/64c65388..85dc52bf

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=572&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=572&range=00-01

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk/pull/572.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/572/head:pull/572

PR: https://git.openjdk.java.net/jdk/pull/572