Switch to clang-r407598b (12.0.2).

Bug: 178106097
Test: build.
Change-Id: I1ce256547fc395a6b440950b4c88f7fe777c86ee
diff --git a/cc/config/global.go b/cc/config/global.go
index c62f784..ee41125 100644
--- a/cc/config/global.go
+++ b/cc/config/global.go
@@ -144,8 +144,8 @@
 
 	// prebuilts/clang default settings.
 	ClangDefaultBase         = "prebuilts/clang/host"
-	ClangDefaultVersion      = "clang-r407598"
-	ClangDefaultShortVersion = "12.0.1"
+	ClangDefaultVersion      = "clang-r407598b"
+	ClangDefaultShortVersion = "12.0.2"
 
 	// Directories with warnings from Android.bp files.
 	WarningAllowedProjects = []string{