tests: make path assertions aware of vendoring

The path of a package can change in a situation where
dependency vendoring is in use.
This change modifies gin's unit tests to allow such paths.

context_test.go

@@ -161,7 +161,7 @@ func TestContextHandlerName(t *testing.T) {
 	c, _, _ := createTestContext()
 	c.handlers = HandlersChain{func(c *Context) {}, handlerNameTest}
 
-	assert.Equal(t, c.HandlerName(), "github.com/gin-gonic/gin.handlerNameTest")
+	assert.Regexp(t, "^(.*/vendor/)?github.com/gin-gonic/gin.handlerNameTest$", c.HandlerName())
 }
 
 func handlerNameTest(c *Context) {