[lsp][bug] find-all references crashes with concurrent map read/write error

[mjames-c]

I attempted to run find all references on a symbol used widely across Canva's very large TS project (containing 98k+ TS files). The LSP crashed with the following error:

fatal error: concurrent map read and map write

goroutine 196467 [running]:
internal/runtime/maps.fatal({0xeb4e9f?, 0xc0000c7330?})
/usr/local/go/src/runtime/panic.go:1058 +0x18
github.com/microsoft/typescript-go/internal/project.(*checkerPool).getRequestCheckerLocked(0xc00021c070, {0xeef35c, 0x2})
<omitted>/typescript-go/internal/project/checkerpool.go:131 +0x76
github.com/microsoft/typescript-go/internal/project.(*checkerPool).GetAllCheckers(0xc00021c070, {0xf71c30, 0xc0d9bf77c0})
<omitted>/typescript-go/internal/project/checkerpool.go:96 +0xa5
github.com/microsoft/typescript-go/internal/compiler.(*Program).getSemanticDiagnosticsForFile(0xc000403500, {0xf71c30, 0xc0d9bf77c0}, 0xc08a9f2588)
<omitted>/typescript-go/internal/compiler/program.go:454 +0x26d
github.com/microsoft/typescript-go/internal/compiler.(*Program).getDiagnosticsHelper(0xc000403500, {0xf71c30, 0xc0d9bf77c0}, 0xc08a9f2588, 0x1, 0x1, 0xc0000c7b80)
<omitted>/typescript-go/internal/compiler/program.go:619 +0xd0
github.com/microsoft/typescript-go/internal/compiler.(*Program).GetSemanticDiagnostics(0xc000403500, {0xf71c30, 0xc0d9bf77c0}, 0xc08a9f2588)
<omitted>/typescript-go/internal/compiler/program.go:394 +0xb9
github.com/microsoft/typescript-go/internal/ls.(*LanguageService).GetDocumentDiagnostics(0xc434f40270, {0xf71c30, 0xc0d9bf77c0}, {0xc001ed2060, 0x51})
<omitted>/typescript-go/internal/ls/diagnostics.go:18 +0x245
github.com/microsoft/typescript-go/internal/lsp.(*Server).handleDocumentDiagnostic(0xc000000380, {0xf71c30, 0xc0d9bf77c0}, 0xc497fd5b00)
<omitted>/typescript-go/internal/lsp/server.go:567 +0x19f
github.com/microsoft/typescript-go/internal/lsp.(*Server).handleRequestOrNotification(0xc000000380, {0xf71c30, 0xc0d9bf77c0}, 0xc497fd5b00)
<omitted>/typescript-go/internal/lsp/server.go:417 +0x399
github.com/microsoft/typescript-go/internal/lsp.(*Server).dispatchLoop.func1()
<omitted>/typescript-go/internal/lsp/server.go:302 +0x65
created by github.com/microsoft/typescript-go/internal/lsp.(*Server).dispatchLoop in goroutine 34
<omitted>/typescript-go/internal/lsp/server.go:320 +0x58c

It's not actually clear to me whether this is a bug with find refs itself or a race between different LSP commands -- I failed to reproduce on subsequent runs of find refs

[jakebailey]

I fixed this in #1169, actually.