RFR: 8161265: [JVMCI] EnableJVMCI should only be required when its not implied by other flags

[Doug Simon]

The -XX:+EnableJVMCI option 1) unlocks code paths in the VM related to JVMCI and 2) is required to unlock all other JVMCI options. However, 1 could be achieved by specific JVMCI options without requiring 2. Since JVMCI is experimental, these options already require -XX:+UnlockExperimentalVMOptions. Having to unlock them twice is redundant and makes for unnecessarily long command lines. For example:

java -XX:+UnlockExperimentalVMOptions -XX:+EnableJVMCI -XX:+UseJVMCICompiler ...

could be:

java -XX:+UnlockExperimentalVMOptions -XX:+UseJVMCICompiler ...

This webrev removes the need for specifying -XX:+EnableJVMCI for these options:

UseJVMCICompiler
JVMCITraceLevel
JVMCICounterSize
JVMCICountersExcludeCompiler
JVMCIUseFastLocking
JVMCINMethodSizeLimit
TraceUncollectedSpeculations

It also significantly simplifies the logic for checking consistency for JVMCI options. The trade off is that when new JVMCI options are added, the logic in JVMCIGlobals::check_jvmci_flags_are_consistent needs to be updated.

Lastly, I took this opportunity to remove the CodeInstallSafepointChecks option as it should always be true.

https://bugs.openjdk.java.net/browse/JDK-8161265
http://cr.openjdk.java.net/~dnsimon/8161265/

-Doug