void fireBlockChanged(MemoryBlock block) {
		if (program != null) {
			program.setChanged(ProgramEvent.MEMORY_BLOCK_CHANGED, block, null);
		}

		// name could have changed
		nameBlockMap = new HashMap<>();
	}
Two blocks have been joined producing newBlock. The block which was eliminated can be
identified using the oldBlockStartAddr.

@param newBlock new joined memory block
@param oldBlockStartAddr original start address of affected block
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/database/mem/MemoryMapDB.java