Revert "Include FIR modules into compiler #KT-30243 Fixed"

This reverts commit 053aa8ca. It causes
"IllegalArgumentException: org.gradle.*.DefaultClassLoaderScope@13fca663
must be locked before it can be used to compute a classpath!"
in Gradle integration tests

idea/testData/gradle/highlighting/complexBuildGradleKts/build.gradle.kts

@@ -113,11 +113,17 @@ extra["compilerModules"] = arrayOf(
     ":compiler:resolution",
     ":compiler:serialization",
     ":compiler:psi",
-    ":compiler:fir:cones",
-    ":compiler:fir:resolve",
-    ":compiler:fir:tree",
-    ":compiler:fir:psi2fir",
-    ":compiler:fir:fir2ir",
+    *if (project.findProperty("fir.enabled") == "true") {
+        arrayOf(
+            ":compiler:fir:cones",
+            ":compiler:fir:resolve",
+            ":compiler:fir:tree",
+            ":compiler:fir:psi2fir",
+            ":compiler:fir:fir2ir"
+        )
+    } else {
+        emptyArray()
+    },
     ":compiler:frontend",
     ":compiler:frontend.common",
     ":compiler:frontend.java",