This commit removes compiler instantiation at startup.
This is because the constructor is invoked during the plugin loading phase,
in which the project has not been completely loaded.
Retrieving `ts.Program` at startup will trigger an `updateGraph` operation,
which could only be called after the Project has loaded completely.
Without this change, the Ivy LS cannot be loaded as a tsserver plugin.
Note that the whole `Compiler` class is temporary, so changes made there are
only for development. Once we have proper integration with ngtsc the
`Compiler` class would be removed.
PR Close#38120