fix UCERF2 thread safety

[Peter Powers]

Threading issues exist when running multiple instances of UCERF2 in the same JVM. Specifically:

• magLen relationships are commonly declared static even though they have a settable fields
• deformation and fault model fetchers are usually only initialized once, but their internal tables are static and may not be fully initialized when accessed by multiple threads
• nnls is unsynchronized

[Peter Powers]

in [8930]

org.opensha.commons.nnls.Nnls.nnls()

• is now synchronized

UCERF2...A_FaultSegmentedSourceGenerator.java

• nnls references are now instance not static
• magLen rel is instance

UCERF2...DeformationModelPrefDataFinal?

• internal maps are tied to instance and not static shared

UCERF2...PrefFaultSectionDataFinal?

• internal maps are tied to instance and not static shared

UCERF2...NSHMP_GridSourceGenerator

• magLen rel is instance