Regression test
JSON updates
Fix leak caused by caching import declarations on resolve
Compiler bootstraps without symbol links
Language service now builds without symbol links
Remove symbol graph
Fix lookup of call, construct and index signatures
Delegate to root type when looking up symbol containers
All compiler baseline tests now pass
All unit tests now pass
Some tweaks to the perf harness
Remove "symbol and diagnostics" type.  (Some remaining work is marked with "PERFREVIEW")
More caching changes to improve type check performance
Update LKG
Fold more type check infrastructure into type resolution (in preparation for removing pullTypeChecker.ts)
Checkpoint commit.  (Lots of stuff still doesn't work, but that's ok!)
Move more type check infrastucture over to resolution
Flatten some property accessors
Flatten more property accesses
Flatten more property accessors