Replace libc++.so.1 with libc++.so

After clang update (with aosp/2590665), clang prebuilts now depend on libc++.so
instead of libc++.so.1.

Bug: 287115146
Test: presubmit
Change-Id: I98803493f69d7f5ee08345cd3bfb9049a496df78
diff --git a/soong/clangprebuilts.go b/soong/clangprebuilts.go
index 9a6b39f..72c96ac 100644
--- a/soong/clangprebuilts.go
+++ b/soong/clangprebuilts.go
@@ -30,15 +30,15 @@
 )
 
 const libclangCppSoFormat = "libclang-cpp.so.%s"
-const libcxxSoName = "libc++.so.1"
-const libcxxabiSoName = "libc++abi.so.1"
+const libcxxSoName = "libc++.so"
+const libcxxabiSoName = "libc++abi.so"
 
 var (
 	// Files included in the llvm-tools filegroup in ../Android.bp
 	llvmToolsFiles = []string{
 		"bin/llvm-symbolizer",
 		"bin/llvm-cxxfilt",
-		"lib/libc++.so.1",
+		"lib/libc++.so",
 	}
 )