Remove testRunner.injectStyleSheet usage from layout tests.

LayoutTests/inspector/elements/styles/styles-disable-then-enable-overriden-ua-expected.txt

Index: LayoutTests/inspector/elements/styles/styles-disable-then-enable-overriden-ua-expected.txt
diff --git a/LayoutTests/inspector/elements/styles/styles-disable-then-enable-overriden-ua-expected.txt b/LayoutTests/inspector/elements/styles/styles-disable-then-enable-overriden-ua-expected.txt
deleted file mode 100644
index 717d80d84b398867f534bf0fbe3ca794b09a6f80..0000000000000000000000000000000000000000
--- a/LayoutTests/inspector/elements/styles/styles-disable-then-enable-overriden-ua-expected.txt
+++ /dev/null
@@ -1,42 +0,0 @@
-Tests that disabling shorthand removes the "overriden" mark from the UA shorthand it overrides.
-
-Before disable
-[expanded] 
-element.style  { ()
-  margin: 10px;
-
-[expanded] 
-#container  { (injected stylesheet)
-/-- overloaded --/   margin: 8px;
-
-[expanded] 
-div  { (user agent stylesheet)
-  display: block;
-
-After disable
-[expanded] 
-element.style  { ()
-/-- overloaded --/ /-- disabled --/   /* margin: 10px; */
-
-[expanded] 
-#container  { (injected stylesheet)
-  margin: 8px;
-
-[expanded] 
-div  { (user agent stylesheet)
-  display: block;
-
-After enable
-[expanded] 
-element.style  { ()
-  margin: 10px;
-
-[expanded] 
-#container  { (injected stylesheet)
-/-- overloaded --/   margin: 8px;
-
-[expanded] 
-div  { (user agent stylesheet)
-  display: block;
-
-