[LL FIR] rename testdata to testData to avoid copyright generation

We exclude testData pattern from copyright scope

analysis/low-level-api-fir/testData/inBlockModification/memberFunWithBodyWithErrorContract.kt

@@ -0,0 +1,10 @@
+import kotlin.contracts.*
+
+class A {
+    fun passLambdaValue(l: ContractBuilder.() -> Unit) {
+        contract(l)
+        <expr>42</expr>
+    }
+}
+
+fun doSmth(i: String) = 4