internal/lsp: don't show an error for "allExperiments" in (options).set

Missed this in CL 260002. Added to the unit tests :)

Change-Id: I81607fd3cbbf021771e09ecd75952f27a622e754
Reviewed-on: https://go-review.googlesource.com/c/tools/+/260005
Trust: Rebecca Stambler <rstambler@golang.org>
Run-TryBot: Rebecca Stambler <rstambler@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Robert Findley <rfindley@google.com>
diff --git a/internal/lsp/source/options.go b/internal/lsp/source/options.go
index a84abe5..90ca263 100644
--- a/internal/lsp/source/options.go
+++ b/internal/lsp/source/options.go
@@ -698,6 +698,10 @@
 	case "experimentalDiagnosticsDelay":
 		result.setDuration(&o.ExperimentalDiagnosticsDelay)
 
+	case "allExperiments":
+		// This setting should be handled before all of the other options are
+		// processed, so do nothing here.
+
 	// Replaced settings.
 	case "experimentalDisabledAnalyses":
 		result.State = OptionDeprecated
diff --git a/internal/lsp/source/options_test.go b/internal/lsp/source/options_test.go
index 0e686b6..a25b97e 100644
--- a/internal/lsp/source/options_test.go
+++ b/internal/lsp/source/options_test.go
@@ -53,6 +53,13 @@
 			value: map[string]interface{}{"generate": true},
 			check: func(o Options) bool { return o.Codelens["generate"] },
 		},
+		{
+			name:  "allExperiments",
+			value: true,
+			check: func(o Options) bool {
+				return true // just confirm that we handle this setting
+			},
+		},
 	}
 
 	for _, test := range tests {