tests: Add $(top_srcdir)/include to AM_CPPFLAGS.

Fixes this build error with make check.

  CC     collision.o
In file included from ../../../../../src/mesa/main/hash_table.h:34:0,
                 from collision.c:31:
../../../../../src/mesa/main/compiler.h:51:53: fatal error: c99_compat.h: No such file or directory

Signed-off-by: Vinson Lee <vlee@freedesktop.org>
1 file changed