Combine vadd_vi, vadd_vx, vadd_vv into one test

This reduces the time for running tests (as it takes around 4 seconds
to start up a new test), instead running vadd's all in one "test", but
still maintains 3 separate files, one for each instruction.

Change-Id: Ic3974f8873a7dcff2155c5e080d010cf1b59c70b

tests/CMakeLists.txt

diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index 3bab2ed..076516a 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -47,30 +47,10 @@
 
 vec_cc_test(
   NAME
-    vadd_vi_test
+    vadd_test
   SRCS
     vadd_vi_test.cpp
-  LINKOPTS
-   -Xlinker --defsym=__itcm_length__=256K
-  TIMEOUT
-    40
-)
-
-vec_cc_test(
-  NAME
-    vadd_vx_test
-  SRCS
     vadd_vx_test.cpp
-  LINKOPTS
-   -Xlinker --defsym=__itcm_length__=256K
-  TIMEOUT
-    40
-)
-
-vec_cc_test(
-  NAME
-    vadd_vv_test
-  SRCS
     vadd_vv_test.cpp
   LINKOPTS
    -Xlinker --defsym=__itcm_length__=256K