private static boolean isDefaultThunk(Symbol sym) {
		return sym.getSource() == SourceType.DEFAULT && (sym instanceof FunctionSymbol) &&
			((FunctionSymbol) sym).isThunk();
	}
Removes the symbol directly

@param sym the symbol to remove.
@return true if the symbol was removed, false otherwise.
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/database/symbol/SymbolManager.java