Remove test mapping file for ImmutabilityAnnotationProcessorUnitTests

The test is already covered in host_unit_tests

Bug: 265439335
Test: none
Change-Id: Ie9ba5591475ae9382d4ce6d418ddb580a60aa007
(cherry picked from commit 94ce5bc05cd61126e69bfaa61ae717c82c8f57d4)
diff --git a/tools/processors/immutability/TEST_MAPPING b/tools/processors/immutability/TEST_MAPPING
deleted file mode 100644
index 4e8e238..0000000
--- a/tools/processors/immutability/TEST_MAPPING
+++ /dev/null
@@ -1,7 +0,0 @@
-{
-    "presubmit": [
-        {
-            "name": "ImmutabilityAnnotationProcessorUnitTests"
-        }
-    ]
-}