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

We exclude testData pattern from copyright scope

analysis/low-level-api-fir/testData/contextCollector/smartCasts/insideLetOnNullableReceiver.txt

@@ -0,0 +1,40 @@
+Tower Data Context:
+    Element 0
+        Scope: FirDefaultStarImportingScope
+    Element 1
+        Scope: FirDefaultSimpleImportingScope
+    Element 2
+        Scope: FirExplicitStarImportingScope
+    Element 3
+        Scope: FirDefaultSimpleImportingScope
+    Element 4
+        Scope: FirDefaultSimpleImportingScope
+    Element 5
+        Scope: FirPackageMemberScope
+    Element 6
+        Scope: FirExplicitSimpleImportingScope
+    Element 7
+        Scope: FirLocalScope
+            Properties:
+                FirValueParameterSymbol param: R|kotlin/String?|
+    Element 8
+        Scope: FirLocalScope
+    Element 9
+        Scope: FirLocalScope
+            Properties:
+                FirValueParameterSymbol it: R|kotlin/String|
+    Element 10
+        Scope: FirLocalScope
+Smart Casts:
+    FirValueParameterSymbol param: R|kotlin/String?|
+    Types:
+        kotlin/Any
+
+FILE: [ResolvedTo(IMPORTS)] insideLetOnNullableReceiver.kt
+    public final [ResolvedTo(BODY_RESOLVE)] fun foo([ResolvedTo(BODY_RESOLVE)] param: R|kotlin/String?|): R|kotlin/String| {
+        R|<local>/param|?.{ $subj$.R|kotlin/let|<R|kotlin/String|, R|kotlin/Nothing|>(<L> = [ResolvedTo(BODY_RESOLVE)] let@fun <anonymous>([ResolvedTo(BODY_RESOLVE)] it: R|kotlin/String|): R|kotlin/Nothing| <inline=Inline, kind=EXACTLY_ONCE>  {
+            ^foo R|<local>/param|
+        }
+        ) }
+        ^foo String()
+    }