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

We exclude testData pattern from copyright scope

analysis/low-level-api-fir/testData/inBlockModification/codeFragments/simple.txt

@@ -0,0 +1,7 @@
+BEFORE MODIFICATION:
+CODE FRAGMENT: {
+    R|<local>/foo|
+}
+
+AFTER MODIFICATION:
+CODE FRAGMENT: { LAZY_BLOCK }