Move three legacy .c files to .cpp.

Test: treehugger
Change-Id: Ic22896d25881fe35f28bad53c5412e3e1d4b2661
diff --git a/libc/Android.bp b/libc/Android.bp
index e4bedba..048cd73 100644
--- a/libc/Android.bp
+++ b/libc/Android.bp
@@ -860,7 +860,7 @@
         "bionic/initgroups.c",
         "bionic/inotify_init.cpp",
         "bionic/ioctl.cpp",
-        "bionic/isatty.c",
+        "bionic/isatty.cpp",
         "bionic/killpg.cpp",
         "bionic/langinfo.cpp",
         "bionic/lchown.cpp",
@@ -931,8 +931,8 @@
         "bionic/rename.cpp",
         "bionic/rmdir.cpp",
         "bionic/scandir.cpp",
-        "bionic/sched_cpualloc.c",
-        "bionic/sched_cpucount.c",
+        "bionic/sched_cpualloc.cpp",
+        "bionic/sched_cpucount.cpp",
         "bionic/sched_getaffinity.cpp",
         "bionic/sched_getcpu.cpp",
         "bionic/semaphore.cpp",