[nrf noup] samples&tests: Restore a few CONFIG_NEWLIB_LIBC_NANO=n

This is a follow-up to commit 9dd570f.

Since in NCS, unlike in vanilla Zephyr, the nano variant of newlib
is the default one, restore entries that disable the nano variant
in one sample and one test that require the full newlib variant.
This patch is supposed to be removed when picolibc becomes the default.

Signed-off-by: Andrzej Głąbek <[email protected]>
Signed-off-by: Dominik Ermel <[email protected]>
(cherry picked from commit 275c2a7)

Author: anangl

tests/lib/newlib/heap_listener/prj.conf

@@ -1,3 +1,4 @@
 CONFIG_ZTEST=y
 CONFIG_NEWLIB_LIBC=y
+CONFIG_NEWLIB_LIBC_NANO=n
 CONFIG_NEWLIB_LIBC_HEAP_LISTENER=y