Stop passing `--test-adapter-path` to `dotnet test` in scripts

this was causing a warning to appear, see microsoft/vstest#3475
don't entirely remember why it was necessary to pass
this, originally `-a`, at all; it's in the first commit d91c477e5

Dist/.BuildTestInConfigX.sh

@@ -7,5 +7,4 @@ config="$1"
 shift
 Dist/.InvokeCLIOnMainSln.sh "test" "$config" \
 	-l "junit;LogFilePath=$PWD/test_output/{assembly}.coverage.xml;MethodFormat=Class;FailureBodyFormat=Verbose" \
-	--test-adapter-path . \
 	"$@"