Add support for Swift Test WebAssembly

Author: shahmishal

docs/ContinuousIntegration.md

@@ -91,6 +91,7 @@ macOS platform               | @swift-ci Please smoke benchmark              | S
 Linux platform               | @swift-ci Please test Linux platform          | Swift Test Linux Platform (smoke test)<br>Swift Test Linux Platform
 Linux platform               | @swift-ci Please clean test Linux platform    | Swift Test Linux Platform (smoke test)<br>Swift Test Linux Platform
 macOS platform               | @swift-ci Please ASAN test                    | Swift ASAN Test macOS Platform
+Linux platform               | @swift-ci Please test WebAssembly             | Swift Test WebAssembly (Ubuntu 20.04)
 
 The core principles of validation testing is that: