[cov,test] Apply OT_NO_COVERAGE to sram exec test

When testing code that is copied and executed from SRAM, coverage
instrumentation can lead to crashes since the relative address
to coverage counters on SRAM becomes invalid.

This patch applies the `OT_NO_COVERAGE` attribute to the `test_stub`
function in `sram_exec_test.c` to prevent the compiler from inserting
coverage counters.

Change-Id: I55641d42b5a6113ec757d8c6ec7fab7f39556347
Signed-off-by: Yi-Hsuan Deng <[email protected]>

Author: sasdf

sw/device/silicon_creator/rom_ext/e2e/handoff/BUILD

@@ -183,6 +183,7 @@ SRAM_EXEC_TESTCASES = [
             "//hw/ip/sram_ctrl/data:sram_ctrl_c_regs",
             "//hw/top_earlgrey/sw/autogen:top_earlgrey",
             "//sw/device/lib/base:abs_mmio",
+            "//sw/device/lib/base:macros",
             "//sw/device/lib/testing/test_framework:ottf_main",
             "//sw/device/silicon_creator/lib:dbg_print",
         ],

sw/device/silicon_creator/rom_ext/e2e/handoff/sram_exec_test.c

@@ -3,6 +3,7 @@
 // SPDX-License-Identifier: Apache-2.0
 
 #include "sw/device/lib/base/abs_mmio.h"
+#include "sw/device/lib/base/macros.h"
 #include "sw/device/lib/testing/test_framework/ottf_main.h"
 #include "sw/device/silicon_creator/lib/dbg_print.h"
 
@@ -15,6 +16,7 @@ enum {
   kBase = TOP_EARLGREY_SRAM_CTRL_MAIN_REGS_BASE_ADDR,
 };
 
+OT_NO_COVERAGE
 int test_stub(void) { return 0x42; }
 
 // SRAM copy of `test_stub` bytecodes.