Resolve RequireByString test suite failures on Ubuntu CI (#1124)

This PR resolves the RequireByString test suite failures in CI on
Ubuntu. The issue was that paths on linux are case sensitive and thus
MacOS/Windows machines simply behaved as if the paths to the test files
were case-insensitive, but the linux machine was unable to find the test
files. Those tests were `#ifdef'd` out, and have been un `#ifdef'd` to
demonstrate these changes work.

tests/RequireByString.test.cpp

@@ -56,15 +56,20 @@ class ReplWithPathFixture
 
         for (int i = 0; i < 20; ++i)
         {
-            if (isDirectory(luauDirAbs + "/Luau/tests") || isDirectory(luauDirAbs + "/Client/Luau/tests"))
+            bool engineTestDir = isDirectory(luauDirAbs + "/Client/Luau/tests");
+            bool luauTestDir = isDirectory(luauDirAbs + "/luau/tests");
+            if (engineTestDir || luauTestDir)
             {
-                if (isDirectory(luauDirAbs + "/Client/Luau/tests"))
+                if (engineTestDir)
                 {
-                    luauDirRel += "/Client";
-                    luauDirAbs += "/Client";
+                    luauDirRel += "/Client/Luau";
+                    luauDirAbs += "/Client/Luau";
+                }
+                else
+                {
+                    luauDirRel += "/luau";
+                    luauDirAbs += "/luau";
                 }
-                luauDirRel += "/Luau";
-                luauDirAbs += "/Luau";
 
                 if (type == PathType::Relative)
                     return luauDirRel;
@@ -209,7 +214,6 @@ TEST_CASE("PathNormalization")
     }
 }
 
-#if 0
 
 TEST_CASE_FIXTURE(ReplWithPathFixture, "RequireSimpleRelativePath")
 {
@@ -390,6 +394,4 @@ TEST_CASE_FIXTURE(ReplWithPathFixture, "RequirePathWithParentAlias")
     assertOutputContainsAll({"true", "result from other_dependency"});
 }
 
-#endif
-
 TEST_SUITE_END();