[clang] [clang][SourceManager] Use `getFileLoc` when computing `getPresumedLoc` (PR #168402)

[Sergej Salnikov via cfe-commits]

================
@@ -9,9 +9,8 @@
 
 #define t(x) x
 
-t(a
-3)
-
-t(b
-__LINE__)
+t(
+  a 3)
----------------
SergejSalnikov wrote:

the problem is that change impact the output of `-E` command. It used to be that macro was expanded by preprocessor on a single line, but now the macro argument preserves the line numbers, so `a 3` used to be rendered on a single line, now that will be 2 lines. (and grep doesn't match well multiline pattern).

https://github.com/llvm/llvm-project/pull/168402