STM32F3 : Fix RTOS GCC_ARM test failed.

remove target with RAM too small for RTOS GCC_ARM.
since newlib is used for RTOS re-entrance suport instead of nano-newlib :
Heap size is reduced because sdata and bss have increased.

Author: jamike

hal/targets.json

@@ -715,6 +715,7 @@
         "progen": {"target": "nucleo-f302r8"},
         "detect_code": ["0705"],
         "device_has": ["ANALOGIN", "ANALOGOUT", "CAN", "I2C", "I2CSLAVE", "INTERRUPTIN", "PORTIN", "PORTINOUT", "PORTOUT", "PWMOUT", "RTC", "SERIAL", "SERIAL_ASYNCH", "SLEEP", "SPI", "SPISLAVE", "STDIO_MESSAGES"],
+        "default_build": "small",        
         "release_versions": ["2"]
     },
     "NUCLEO_F303K8": {
@@ -726,6 +727,7 @@
         "inherits": ["Target"],
         "progen": {"target": "nucleo-f303k8"},
         "detect_code": ["0775"],
+        "default_build": "small",
         "device_has": ["ANALOGIN", "ANALOGOUT", "CAN", "I2C", "I2CSLAVE", "INTERRUPTIN", "PORTIN", "PORTINOUT", "PORTOUT", "PWMOUT", "RTC", "SERIAL", "SLEEP", "SPI", "SPISLAVE", "STDIO_MESSAGES"],
         "release_versions": ["2"]
     },
@@ -751,6 +753,7 @@
         "progen": {"target": "nucleo-f334r8"},
         "detect_code": ["0735"],
         "device_has": ["ANALOGIN", "ANALOGOUT", "CAN", "I2C", "I2CSLAVE", "INTERRUPTIN", "PORTIN", "PORTINOUT", "PORTOUT", "PWMOUT", "RTC", "SERIAL", "SERIAL_ASYNCH", "SLEEP", "SPI", "SPISLAVE", "STDIO_MESSAGES"],
+        "default_build": "small",
         "release_versions": ["2"]
     },
     "NUCLEO_F401RE": {
@@ -1025,7 +1028,8 @@
         "progen": {"target": "disco-f334c8"},
         "detect_code": ["0810"],
         "device_has": ["ANALOGIN", "ANALOGOUT", "I2C", "I2CSLAVE", "INTERRUPTIN", "PORTIN", "PORTINOUT", "PORTOUT", "PWMOUT", "RTC", "RTC_LSI", "SERIAL", "SERIAL_ASYNCH", "SLEEP", "SPI", "SPISLAVE", "STDIO_MESSAGES"],
-        "release_versions": ["2"]
+        "default_build": "small",        
+	"release_versions": ["2"]
     },
     "DISCO_F407VG": {
         "inherits": ["Target"],