tests: cleanup test_build

- Kconfig test does not really need to build on all platforms
- nmi test is already in tests/arch/arm/arm_runtime_nmi
- we have plenty of tests with newlib enabled.

Signed-off-by: Anas Nashif <anas.nashif@intel.com>

tests/misc/test_build/newlib.conf

@@ -1,7 +0,0 @@
-CONFIG_TEST=y
-CONFIG_DEBUG=y
-CONFIG_STDOUT_CONSOLE=y
-CONFIG_NEWLIB_LIBC=y
-# turn bluetooth of until we resolve printf formatter
-# difference between newlib & min-libc
-CONFIG_BT=n

tests/misc/test_build/runtime_nmi.conf

@@ -1,2 +0,0 @@
-CONFIG_TEST=y
-CONFIG_RUNTIME_NMI=y

tests/misc/test_build/testcase.yaml

@@ -3,16 +3,6 @@ tests:
     build_only: true
     extra_args: CONF_FILE=debug.conf
     tags: build_test
-  test_newlib:
-    build_only: true
-    extra_args: CONF_FILE=newlib.conf
-    tags: build_test
-    filter: TOOLCHAIN_HAS_NEWLIB == 1
-  test_runtime_nmi:
-    arch_whitelist: arm
-    build_only: true
-    extra_args: CONF_FILE=runtime_nmi.conf
-    tags: build_test
   test_mcuboot_bootloader:
     tags: build_test
     build_only: true
@@ -22,5 +12,6 @@ tests:
   test_utf8_in_kconfig_values:
     build_only: true
     tags: build_test
+    platform_whitelist: native_posix
     extra_configs:
       - CONFIG_KERNEL_BIN_NAME="A_kconfig_value_with_a_utf8_char_in_it_Bøe_"