Revert "Overwrite sync expect fn with expectAsync (#545)"

This reverts commit c9a63ad.

src/addMatchers.ts

@@ -48,13 +48,8 @@ export const addMatchers = (): any => {
     expectLib = global.jasmine
 
     return expectLib.getEnv().beforeAll(function addExpectWebdriverIOMatchers(): void {
+        expectLib.addMatchers({ ...matchers })
         expectLib.addAsyncMatchers({ ...matchers })
-
-        /**
-         * we can't use WebdriverIO async matchers with Jasmines synchronous expect
-         * library as we get something like `Error: Expected [object Promise] to be existing.`
-         */
-        global.expect = global.expectAsync as any
     })
 }