Invalidate cache on Ghidra server restart

[unknown321]

Symbols provided by Ghidra are locked to active file during server configuration.

Reproducing:

1. Open two files
2. Start server on binary 1
3. Start server on binary 2, same settings as bin 1
4. Get symbols, notice, that symbols are from binary 1. Expected symbols from binary 2.

# start bin1 server
$ curl -s http://127.0.0.1:3662/RPC2 -d "<methodCall><methodName>d2d.elf_info</methodName><params></params></methodCall>" | grep -oP "<name>name</name><value>(.*?)</value>"`
<name>name</name><value>binary 1</value>
# start bin2 server
$ curl -s http://127.0.0.1:3662/RPC2 -d "<methodCall><methodName>d2d.elf_info</methodName><params></params></methodCall>" | grep -oP "<name>name</name><value>(.*?)</value>"`
<name>name</name><value>binary 1</value>

As for now this is fixed only by restarting ghidra.

This problem rises when you need to switch between library and binary during debugging session.