ICU-20202 Merge #ifdef __cplusplus blocks.

For historical reasons (commit 3b12074b40),
all C++ code (even #include statements) in cmemory.h is contained in an
#ifdef block at the end of the file. A recent bugfix inadvertently added
an additional #ifdef __cplusplus block at the beginning of the file to
add a new #include statement so that C++ #include statements now are
found in two places (commit 1bad36b91a).

icu4c/source/common/cmemory.h

@@ -32,10 +32,6 @@
 #include <string.h>
 #include "unicode/localpointer.h"
 
-#ifdef __cplusplus
-#include "unicode/uobject.h"
-#endif
-
 #if U_DEBUG && defined(UPRV_MALLOC_COUNT)
 #include <stdio.h>
 #endif
@@ -127,6 +123,7 @@ uprv_deleteUObject(void *obj);
 #ifdef __cplusplus
 
 #include <utility>
+#include "unicode/uobject.h"
 
 U_NAMESPACE_BEGIN