RFR(XS) 8189140 - SystemDictionaryShared::initialize() should be renamed to be more meaningful

[Ioi Lam]

https://bugs.openjdk.java.net/browse/JDK-8189140
http://cr.openjdk.java.net/~iklam/jdk11/8189140-rename-system-dict-shared-initialize.v01/

Summary:

1. Removed the forced initialization of a few classes used by AppCDS at 
JVM start-up.
    Instead, initialize these class on demand by calling 
InstanceKlass::initialize, which
    is a quick no-op if the class is already initialized.

2. The only initialization left is that of a global lock. So I renamed 
the function
    to SystemDictionaryShared::initialize_locks().

3. I moved the call of this function from 
SystemDictionary::compute_java_loaders() to
SystemDictionary::initialize() where it seems to fit.

Testing with hs-tiers 1 and 2.

Thanks
- Ioi