compiler-rt: Rename .cc file in lib/sanitizer_common to .cpp

See https://reviews.llvm.org/D58620 for discussion, and for the commands
I ran. In addition I also ran

  for f in $(svn diff | diffstat | grep .cc | cut -f 2 -d ' '); do rg $f . ; done

and manually updated (many) references to renamed files found by that.

llvm-svn: 367463
GitOrigin-RevId: 65492d959b17aa428f55bbde72af3f2c14711242
diff --git a/FuzzerTracePC.cpp b/FuzzerTracePC.cpp
index 4a1308d..c473577 100644
--- a/FuzzerTracePC.cpp
+++ b/FuzzerTracePC.cpp
@@ -173,7 +173,7 @@
 }
 
 /// \return the address of the next instruction.
-/// Note: the logic is copied from `sanitizer_common/sanitizer_stacktrace.cc`
+/// Note: the logic is copied from `sanitizer_common/sanitizer_stacktrace.cpp`
 ALWAYS_INLINE uintptr_t TracePC::GetNextInstructionPc(uintptr_t PC) {
 #if defined(__mips__)
   return PC + 8;