@Override
				public int read() throws IOException {
					return fillByte;
				}
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