Update comments regarding the zeroize program

This commit updates comments regarding the moved zeroize files.

Signed-off-by: Harry Ramsey <harry.ramsey@arm.com>

tests/programs/test_zeroize.gdb

@@ -7,7 +7,7 @@
 #
 # Run a test using the debugger to check that the mbedtls_platform_zeroize()
 # function in platform_util.h is not being optimized out by the compiler. To do
-# so, the script loads the test program at programs/test/zeroize.c and sets a
+# so, the script loads the test program at programs/test/zeroize and sets a
 # breakpoint at the last return statement in main(). When the breakpoint is
 # hit, the debugger manually checks the contents to be zeroized and checks that
 # it is actually cleared.

tests/programs/zeroize.c

@@ -4,7 +4,7 @@
  * This is a simple test application used for debugger-driven testing to check
  * whether calls to mbedtls_platform_zeroize() are being eliminated by compiler
  * optimizations. This application is used by the GDB script at
- * tests/scripts/test_zeroize.gdb: the script sets a breakpoint at the last
+ * tests/programs/test_zeroize.gdb: the script sets a breakpoint at the last
  * return statement in the main() function of this program. The debugger
  * facilities are then used to manually inspect the memory and verify that the
  * call to mbedtls_platform_zeroize() was not eliminated.