Add test for search result resize width

Author: GuillaumeGomez

src/test/rustdoc-gui/search-result-display.goml

@@ -0,0 +1,12 @@
+goto: file://|DOC_PATH|/test_docs/index.html
+size: (900, 1000)
+write: (".search-input", "test")
+// Waiting for the search results to appear...
+wait-for: "#titles"
+// The width is returned by "getComputedStyle" which returns the exact number instead of the
+// CSS rule which is "50%"...
+assert: (".search-results div.desc", {"width": "320px"})
+size: (600, 100)
+// As counter-intuitive as it may seem, in this width, the width is "100%", which is why
+// when computed it's larger.
+assert: (".search-results div.desc", {"width": "570px"})