Revert "Upgrade to clang-r530567"

This reverts commit b4f05f1a05046e184417e12a0081442fac4ec41e.

Reason for revert: Likely culprit for b/352459464  - verifying through ABTD before revert submission. This is part of the standard investigation process, and does not mean your CL will be reverted.

Change-Id: Iaea4511402b2818904f84e512f4f77487d0efafc
diff --git a/cc/config/global.go b/cc/config/global.go
index bf2502f..62a4765 100644
--- a/cc/config/global.go
+++ b/cc/config/global.go
@@ -397,8 +397,8 @@
 
 	// prebuilts/clang default settings.
 	ClangDefaultBase         = "prebuilts/clang/host"
-	ClangDefaultVersion      = "clang-r530567"
-	ClangDefaultShortVersion = "19"
+	ClangDefaultVersion      = "clang-r522817"
+	ClangDefaultShortVersion = "18"
 
 	// Directories with warnings from Android.bp files.
 	WarningAllowedProjects = []string{