test/runTest.ts: add missing space in error message

Change-Id: I78c358e40b368a8ef9eb5c188126cae54762e280
Reviewed-on: https://go-review.googlesource.com/c/vscode-go/+/540077
TryBot-Result: kokoro <[email protected]>
Commit-Queue: Suzy Mueller <[email protected]>
Reviewed-by: Robert Findley <[email protected]>
Run-TryBot: Suzy Mueller <[email protected]>

Author: suzmue

test/runTest.ts

@@ -37,7 +37,7 @@ async function main() {
 			]
 		});
 	} catch (err) {
-		console.error('Failed to run integration tests' + err);
+		console.error('Failed to run integration tests: ' + err);
 		failed = true;
 	}
 
@@ -59,7 +59,7 @@ async function main() {
 			]
 		});
 	} catch (err) {
-		console.error('Failed to run gopls tests' + err);
+		console.error('Failed to run gopls tests: ' + err);
 		failed = true;
 	}