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

We exclude testData pattern from copyright scope

analysis/low-level-api-fir/testData/inBlockModification/entireFunctionBodyScript.txt

@@ -0,0 +1,6 @@
+BEFORE MODIFICATION:
+public final [ResolvedTo(BODY_RESOLVE)] fun doo(): R|kotlin/Unit| {
+}
+
+AFTER MODIFICATION:
+public final [ResolvedTo(ANNOTATIONS_ARGUMENTS_MAPPING)] fun doo(): R|kotlin/Unit| { LAZY_BLOCK }