pairings-api investigate PairingFriendlyCurveProvider issue in multi-threaded environment

[mxtartaglia-sl]

@derektriley reported an issue with the loading of the SPI.

Some times, It seems that in multithreaded environments we are receiving
java.util.NoSuchElementException: A PairingFriendlyCurveProvider implementation for ALT_BN128 was not found

The stacktrace looks like:

   	○ ServicesMain::main
   		§ initNodeSecurity
   			□ CryptoStatic::generateKeysAndCerts(addressBook);
   				® Loops over AddressBook
   				® Submits to a thread pool
   				® KeysAndCerts.generate
   					◊ New code "BlsKeyPair blsKeyPair = CryptoStatic.generateBlsKeyPair();"
   					◊ Throws 

It does point out to a race condition in the code.