perf: optimize sizeof CBLSLazyWrapper

It reduces memory consumption for classes CBLSLazySignature and CBLSLazyPublicKey

    sizeof(CBLSLazyPublicKey)=344 down to 336
    sizeof(CBLSLazySignature)=536 down to 528

During full index close to ~1Bln of CBLSLazyPublicKey objects are created and destroyed
as members of CDeterministicMNState and CSimplifiedMNListEntry with peak in memory close to ~1Mln

It gave a bit of RAM saving (roughly 8Mb in peak) and a bit of CPU saving by being
a more cache friendly.

CBLSLazySignature is not used as widely as CBLSLazyPublicKey

Author: knst

src/bls/bls.h

@@ -391,13 +391,14 @@ class CBLSLazyWrapper
     mutable std::mutex mutex;
 
     mutable std::array<uint8_t, BLSObject::SerSize> vecBytes;
-    // Indicates if the value contained in vecBytes is valid
-    mutable bool bufValid{false};
-    mutable bool bufLegacyScheme{true};
 
     mutable BLSObject obj;
     mutable bool objInitialized{false};
 
+    // Indicates if the value contained in vecBytes is valid
+    mutable bool bufValid{false};
+    mutable bool bufLegacyScheme{true};
+
     mutable uint256 hash;
 
 public: