Renderscript: change extension .rs to .rscript

Reserve .rs extension for Rust.

Bug: 137365032
Test: make checkbuild
Test: cd frameworks/compile/slang/tests
    ./slang_tests.py
Test: atest CtsRenderscriptTestCases
Test: CtsRsCppTestCases

Exempt-From-Owner-Approval: Clean CP
Change-Id: Ibfccb4f52b74f9ac95c373f48d775254ba77288d
Merged-In: Ibfccb4f52b74f9ac95c373f48d775254ba77288d
(cherry picked from commit 480864f1b013ef4d103ce76cfebb7404f339ae61)
(cherry picked from commit f9b4f4b3e4c8ba8e6c516d26c208746ae747049f)
diff --git a/core/definitions.mk b/core/definitions.mk
index 3df5438..f6472fe 100644
--- a/core/definitions.mk
+++ b/core/definitions.mk
@@ -364,7 +364,7 @@
 ###########################################################
 
 define all-renderscript-files-under
-$(call find-subdir-files,$(1) \( -name "*.rs" -or -name "*.fs" \) -and -not -name ".*")
+$(call find-subdir-files,$(1) \( -name "*.rscript" -or -name "*.fs" \) -and -not -name ".*")
 endef
 
 ###########################################################