[clang] [clang] Fix incorrect line numbers with -E and raw string (#47577) (PR #77021)

[Steve Cornett via cfe-commits]

================
@@ -0,0 +1,6 @@
+// RUN: %clang_cc1 -E %s | FileCheck %s
+// CHECK: AAA
+// CHECK-NEXT: BBB
+R"(
+AAA)"
+BBB
----------------
stevecor wrote:

This test demonstrates that the line `AAA` is followed immediately by the line `BBB` with no intervening blank line. Without the fix, there is an incorrect blank line between them. This test fails without the fix.

https://github.com/llvm/llvm-project/pull/77021