[Analysis API] Migrate existing code fragment tests to the new API

analysis/analysis-api/testData/components/compilerFacility/compilationMultiModule/codeFragments/compilerPluginUsage.fragment.kt

@@ -1,8 +0,0 @@
-@org.jetbrains.kotlin.fir.plugin.AllOpen
-class Foo {
-    fun call() {}
-}
-
-class Bar : Foo() {}
-
-Bar().call()

analysis/analysis-api/testData/components/compilerFacility/compilationMultiModule/codeFragments/compilerPluginUsage.kt

@@ -1,5 +1,23 @@
 // WITH_FIR_TEST_COMPILER_PLUGIN
 
+// MODULE: context
+// FILE: context.kt
+
 fun test() {
-    <caret>val x = 0
-}
+    <caret_context>val x = 0
+}
+
+
+// MODULE: main
+// MODULE_KIND: CodeFragment
+
+// FILE: fragment.kt
+// CODE_FRAGMENT_KIND: BLOCK
+@org.jetbrains.kotlin.fir.plugin.AllOpen
+class Foo {
+    fun call() {}
+}
+
+class Bar : Foo() {}
+
+Bar().call()