gopls/internal/lsp/fake: don't set a completion budget for tests

We were already setting an arbitrarily high completion budget of 10s for
tests, but this appears to be causing flakes in the heavily parallelized
marker tests on slow builders (e.g. golang/go#60584).

No reason to have any budget at all: any tests/benchmarks that depend
on the budget should set it explicitly.

For golang/go#60584

Change-Id: Ic5e84d483fdffb58b801aae7b814ff705e6ecee9
Reviewed-on: https://go-review.googlesource.com/c/tools/+/531556
Auto-Submit: Robert Findley <[email protected]>
Reviewed-by: Peter Weinberger <[email protected]>
LUCI-TryBot-Result: Go LUCI <[email protected]>

gopls/internal/lsp/fake/editor.go

@@ -235,9 +235,9 @@ func makeSettings(sandbox *Sandbox, config EditorConfig) map[string]interface{}
 		// asynchronous operations being completed (such as diagnosing a snapshot).
 		"verboseWorkDoneProgress": true,
 
-		// Set a generous completion budget, so that tests don't flake because
+		// Set an unlimited completion budget, so that tests don't flake because
 		// completions are too slow.
-		"completionBudget": "10s",
+		"completionBudget": "0s",
 	}
 
 	for k, v := range config.Settings {