Rename `tsan/race_range_pc.cc` to `test/tsan/race_range_pc.cpp`.

The old suffix was preventing it from being executed by default.

diff --git a/compiler-rt/test/tsan/race_range_pc.cc b/compiler-rt/test/tsan/race_range_pc.cpp
similarity index 100%
rename from compiler-rt/test/tsan/race_range_pc.cc
rename to compiler-rt/test/tsan/race_range_pc.cpp